diff --git a/bridges/relays/bin-substrate/src/cli/bridge.rs b/bridges/relays/bin-substrate/src/cli/bridge.rs
index 2184903e01..5a5715699c 100644
--- a/bridges/relays/bin-substrate/src/cli/bridge.rs
+++ b/bridges/relays/bin-substrate/src/cli/bridge.rs
@@ -17,7 +17,7 @@
 use structopt::clap::arg_enum;
 
 arg_enum! {
-	#[derive(Debug)]
+	#[derive(Debug, PartialEq, Eq)]
 	/// Supported full bridges (headers + messages).
 	pub enum FullBridge {
 		MillauToRialto,
@@ -59,9 +59,9 @@ macro_rules! select_full_bridge {
 				#[allow(unused_imports)]
 				use crate::rialto_millau::millau_messages_to_rialto::run as relay_messages;
 
-				// Send-message
+				// Send-message / Estimate-fee
 				#[allow(unused_imports)]
-				use bp_millau::TO_MILLAU_ESTIMATE_MESSAGE_FEE_METHOD as ESTIMATE_MESSAGE_FEE_METHOD;
+				use bp_rialto::TO_RIALTO_ESTIMATE_MESSAGE_FEE_METHOD as ESTIMATE_MESSAGE_FEE_METHOD;
 				// Send-message
 				#[allow(unused_imports)]
 				use millau_runtime::rialto_account_ownership_digest as account_ownership_digest;
@@ -81,9 +81,10 @@ macro_rules! select_full_bridge {
 				#[allow(unused_imports)]
 				use crate::rialto_millau::rialto_messages_to_millau::run as relay_messages;
 
-				// Send-message
+				// Send-message / Estimate-fee
 				#[allow(unused_imports)]
-				use bp_rialto::TO_RIALTO_ESTIMATE_MESSAGE_FEE_METHOD as ESTIMATE_MESSAGE_FEE_METHOD;
+				use bp_millau::TO_MILLAU_ESTIMATE_MESSAGE_FEE_METHOD as ESTIMATE_MESSAGE_FEE_METHOD;
+
 				// Send-message
 				#[allow(unused_imports)]
 				use rialto_runtime::millau_account_ownership_digest as account_ownership_digest;
diff --git a/bridges/relays/bin-substrate/src/cli/encode_call.rs b/bridges/relays/bin-substrate/src/cli/encode_call.rs
index b5cdaaa1d3..6e1130cffc 100644
--- a/bridges/relays/bin-substrate/src/cli/encode_call.rs
+++ b/bridges/relays/bin-substrate/src/cli/encode_call.rs
@@ -35,7 +35,7 @@ pub struct EncodeCall {
 ///
 /// Note this enum may be used in the context of both Source (as part of `encode-call`)
 /// and Target chain (as part of `encode-message/send-message`).
-#[derive(StructOpt, Debug)]
+#[derive(StructOpt, Debug, PartialEq, Eq)]
 pub enum Call {
 	/// Raw bytes for the message
 	Raw {
diff --git a/bridges/relays/bin-substrate/src/cli/encode_message.rs b/bridges/relays/bin-substrate/src/cli/encode_message.rs
index 5ef668864e..a29aa8597d 100644
--- a/bridges/relays/bin-substrate/src/cli/encode_message.rs
+++ b/bridges/relays/bin-substrate/src/cli/encode_message.rs
@@ -19,7 +19,7 @@ use crate::select_full_bridge;
 use structopt::StructOpt;
 
 /// Generic message payload.
-#[derive(StructOpt, Debug)]
+#[derive(StructOpt, Debug, PartialEq, Eq)]
 pub enum MessagePayload {
 	/// Raw, SCALE-encoded `MessagePayload`.
 	Raw {
diff --git a/bridges/relays/bin-substrate/src/cli/estimate_fee.rs b/bridges/relays/bin-substrate/src/cli/estimate_fee.rs
new file mode 100644
index 0000000000..4e39ad351e
--- /dev/null
+++ b/bridges/relays/bin-substrate/src/cli/estimate_fee.rs
@@ -0,0 +1,128 @@
+// Copyright 2019-2021 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity Bridges Common is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
+
+use crate::cli::bridge::FullBridge;
+use crate::cli::{Balance, CliChain, HexBytes, HexLaneId, SourceConnectionParams};
+use crate::select_full_bridge;
+use codec::{Decode, Encode};
+use relay_substrate_client::{Chain, ChainWithBalances};
+use structopt::StructOpt;
+
+/// Estimate Delivery & Dispatch Fee command.
+#[derive(StructOpt, Debug, PartialEq, Eq)]
+pub struct EstimateFee {
+	/// A bridge instance to encode call for.
+	#[structopt(possible_values = &FullBridge::variants(), case_insensitive = true)]
+	bridge: FullBridge,
+	#[structopt(flatten)]
+	source: SourceConnectionParams,
+	/// Hex-encoded id of lane that will be delivering the message.
+	#[structopt(long, default_value = "00000000")]
+	lane: HexLaneId,
+	/// Payload to send over the bridge.
+	#[structopt(flatten)]
+	payload: crate::cli::encode_message::MessagePayload,
+}
+
+impl EstimateFee {
+	/// Run the command.
+	pub async fn run(self) -> anyhow::Result<()> {
+		let Self {
+			source,
+			bridge,
+			lane,
+			payload,
+		} = self;
+
+		select_full_bridge!(bridge, {
+			let source_client = source.to_client::<Source>().await?;
+			let lane = lane.into();
+			let payload = Source::encode_message(payload).map_err(|e| anyhow::format_err!("{:?}", e))?;
+
+			let fee: <Source as ChainWithBalances>::NativeBalance =
+				estimate_message_delivery_and_dispatch_fee(&source_client, ESTIMATE_MESSAGE_FEE_METHOD, lane, payload)
+					.await?;
+
+			log::info!(target: "bridge", "Fee: {:?}", Balance(fee as _));
+			println!("{}", fee);
+			Ok(())
+		})
+	}
+}
+
+pub(crate) async fn estimate_message_delivery_and_dispatch_fee<Fee: Decode, C: Chain, P: Encode>(
+	client: &relay_substrate_client::Client<C>,
+	estimate_fee_method: &str,
+	lane: bp_messages::LaneId,
+	payload: P,
+) -> anyhow::Result<Fee> {
+	let encoded_response = client
+		.state_call(estimate_fee_method.into(), (lane, payload).encode().into(), None)
+		.await?;
+	let decoded_response: Option<Fee> =
+		Decode::decode(&mut &encoded_response.0[..]).map_err(relay_substrate_client::Error::ResponseParseFailed)?;
+	let fee = decoded_response
+		.ok_or_else(|| anyhow::format_err!("Unable to decode fee from: {:?}", HexBytes(encoded_response.to_vec())))?;
+	Ok(fee)
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::cli::encode_call;
+	use sp_core::crypto::Ss58Codec;
+
+	#[test]
+	fn should_parse_cli_options() {
+		// given
+		let alice = sp_keyring::AccountKeyring::Alice.to_account_id().to_ss58check();
+
+		// when
+		let res = EstimateFee::from_iter(vec![
+			"estimate_fee",
+			"RialtoToMillau",
+			"--source-port",
+			"1234",
+			"call",
+			"--sender",
+			&alice,
+			"remark",
+			"--remark-payload",
+			"1234",
+		]);
+
+		// then
+		assert_eq!(
+			res,
+			EstimateFee {
+				bridge: FullBridge::RialtoToMillau,
+				lane: HexLaneId([0, 0, 0, 0]),
+				source: SourceConnectionParams {
+					source_host: "127.0.0.1".into(),
+					source_port: 1234,
+					source_secure: false,
+				},
+				payload: crate::cli::encode_message::MessagePayload::Call {
+					sender: alice.parse().unwrap(),
+					call: encode_call::Call::Remark {
+						remark_payload: Some(HexBytes(vec![0x12, 0x34])),
+						remark_size: None,
+					}
+				}
+			}
+		);
+	}
+}
diff --git a/bridges/relays/bin-substrate/src/cli/mod.rs b/bridges/relays/bin-substrate/src/cli/mod.rs
index 960e85ea92..c77d5071db 100644
--- a/bridges/relays/bin-substrate/src/cli/mod.rs
+++ b/bridges/relays/bin-substrate/src/cli/mod.rs
@@ -18,7 +18,6 @@
 
 use std::convert::TryInto;
 
-use crate::rialto_millau::cli as rialto_millau;
 use bp_messages::LaneId;
 use codec::{Decode, Encode};
 use frame_support::weights::Weight;
@@ -28,12 +27,13 @@ use structopt::{clap::arg_enum, StructOpt};
 pub(crate) mod bridge;
 pub(crate) mod encode_call;
 pub(crate) mod encode_message;
+pub(crate) mod estimate_fee;
+pub(crate) mod send_message;
 
 mod derive_account;
 mod init_bridge;
 mod relay_headers;
 mod relay_messages;
-mod send_message;
 
 /// Parse relay CLI args.
 pub fn parse_args() -> Command {
@@ -75,7 +75,7 @@ pub enum Command {
 	/// the bridge.
 	EncodeMessage(encode_message::EncodeMessage),
 	/// Estimate Delivery and Dispatch Fee required for message submission to messages pallet.
-	EstimateFee(EstimateFee),
+	EstimateFee(estimate_fee::EstimateFee),
 	/// Given a source chain `AccountId`, derive the corresponding `AccountId` for the target chain.
 	DeriveAccount(derive_account::DeriveAccount),
 }
@@ -97,23 +97,6 @@ impl Command {
 	}
 }
 
-/// Estimate Delivery & Dispatch Fee command.
-#[derive(StructOpt)]
-pub enum EstimateFee {
-	#[structopt(flatten)]
-	RialtoMillau(rialto_millau::EstimateFee),
-}
-
-impl EstimateFee {
-	/// Run the command.
-	pub async fn run(self) -> anyhow::Result<()> {
-		match self {
-			Self::RialtoMillau(arg) => arg.run().await?,
-		}
-		Ok(())
-	}
-}
-
 arg_enum! {
 	#[derive(Debug)]
 	/// The origin to use when dispatching the message on the target chain.
@@ -127,7 +110,7 @@ arg_enum! {
 }
 
 /// Generic balance type.
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Balance(pub u128);
 
 impl std::fmt::Display for Balance {
@@ -242,7 +225,7 @@ pub trait CliChain: relay_substrate_client::Chain {
 }
 
 /// Lane id.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct HexLaneId(pub LaneId);
 
 impl From<HexLaneId> for LaneId {
@@ -262,7 +245,7 @@ impl std::str::FromStr for HexLaneId {
 }
 
 /// Nicer formatting for raw bytes vectors.
-#[derive(Default, Encode, Decode)]
+#[derive(Default, Encode, Decode, PartialEq, Eq)]
 pub struct HexBytes(pub Vec<u8>);
 
 impl std::str::FromStr for HexBytes {
@@ -321,7 +304,7 @@ impl From<PrometheusParams> for relay_utils::metrics::MetricsParams {
 }
 
 /// Either explicit or maximal allowed value.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ExplicitOrMaximal<V> {
 	/// User has explicitly specified argument value.
 	Explicit(V),
@@ -353,7 +336,7 @@ macro_rules! declare_chain_options {
 	($chain:ident, $chain_prefix:ident) => {
 		paste::item! {
 			#[doc = $chain " connection params."]
-			#[derive(StructOpt)]
+			#[derive(StructOpt, Debug, PartialEq, Eq)]
 			pub struct [<$chain ConnectionParams>] {
 				#[doc = "Connect to " $chain " node at given host."]
 				#[structopt(long, default_value = "127.0.0.1")]
@@ -367,7 +350,7 @@ macro_rules! declare_chain_options {
 			}
 
 			#[doc = $chain " signing params."]
-			#[derive(StructOpt)]
+			#[derive(StructOpt, Debug, PartialEq, Eq)]
 			pub struct [<$chain SigningParams>] {
 				#[doc = "The SURI of secret key to use when transactions are submitted to the " $chain " node."]
 				#[structopt(long)]
diff --git a/bridges/relays/bin-substrate/src/cli/send_message.rs b/bridges/relays/bin-substrate/src/cli/send_message.rs
index e6ab7dcfa7..64448f0f1d 100644
--- a/bridges/relays/bin-substrate/src/cli/send_message.rs
+++ b/bridges/relays/bin-substrate/src/cli/send_message.rs
@@ -16,6 +16,7 @@
 
 use crate::cli::bridge::FullBridge;
 use crate::cli::encode_call::{self, CliEncodeCall};
+use crate::cli::estimate_fee::estimate_message_delivery_and_dispatch_fee;
 use crate::cli::{
 	Balance, CliChain, ExplicitOrMaximal, HexBytes, HexLaneId, Origins, SourceConnectionParams, SourceSigningParams,
 	TargetSigningParams,
@@ -26,6 +27,7 @@ use pallet_bridge_dispatch::{CallOrigin, MessagePayload};
 use relay_substrate_client::{Chain, TransactionSignScheme};
 use sp_core::{Bytes, Pair};
 use sp_runtime::{traits::IdentifyAccount, AccountId32, MultiSignature, MultiSigner};
+use std::fmt::Debug;
 use structopt::StructOpt;
 
 /// Send bridge message.
@@ -84,12 +86,12 @@ impl SendMessage {
 				let target_call_weight = prepare_call_dispatch_weight(
 					dispatch_weight,
 					ExplicitOrMaximal::Explicit(target_call.get_dispatch_info().weight),
-					crate::rialto_millau::compute_maximal_message_dispatch_weight(Target::max_extrinsic_weight()),
+					compute_maximal_message_dispatch_weight(Target::max_extrinsic_weight()),
 				);
 				let source_sender_public: MultiSigner = source_sign.public().into();
 				let source_account_id = source_sender_public.into_account();
 
-				crate::rialto_millau::message_payload(
+				message_payload(
 					Target::RUNTIME_VERSION.spec_version,
 					target_call_weight,
 					match origin {
@@ -127,14 +129,14 @@ impl SendMessage {
 			let lane = self.lane.clone().into();
 			let fee = match self.fee {
 				Some(fee) => fee,
-				None => crate::rialto_millau::estimate_message_delivery_and_dispatch_fee::<
-					<Source as relay_substrate_client::ChainWithBalances>::NativeBalance,
-					_,
-					_,
-				>(&source_client, ESTIMATE_MESSAGE_FEE_METHOD, lane, payload.clone())
-				.await?
-				.map(|v| Balance(v as _))
-				.ok_or_else(|| anyhow::format_err!("Failed to estimate message fee. Message is too heavy?"))?,
+				None => Balance(
+					estimate_message_delivery_and_dispatch_fee::<
+						<Source as relay_substrate_client::ChainWithBalances>::NativeBalance,
+						_,
+						_,
+					>(&source_client, ESTIMATE_MESSAGE_FEE_METHOD, lane, payload.clone())
+					.await? as _,
+				),
 			};
 			let dispatch_weight = payload.weight;
 			let send_message_call = Source::encode_call(&encode_call::Call::BridgeSendMessage {
@@ -192,6 +194,47 @@ fn prepare_call_dispatch_weight(
 	}
 }
 
+pub(crate) fn message_payload<SAccountId, TPublic, TSignature>(
+	spec_version: u32,
+	weight: Weight,
+	origin: CallOrigin<SAccountId, TPublic, TSignature>,
+	call: &impl Encode,
+) -> MessagePayload<SAccountId, TPublic, TSignature, Vec<u8>>
+where
+	SAccountId: Encode + Debug,
+	TPublic: Encode + Debug,
+	TSignature: Encode + Debug,
+{
+	// Display nicely formatted call.
+	let payload = MessagePayload {
+		spec_version,
+		weight,
+		origin,
+		call: HexBytes::encode(call),
+	};
+
+	log::info!(target: "bridge", "Created Message Payload: {:#?}", payload);
+	log::info!(target: "bridge", "Encoded Message Payload: {:?}", HexBytes::encode(&payload));
+
+	// re-pack to return `Vec<u8>`
+	let MessagePayload {
+		spec_version,
+		weight,
+		origin,
+		call,
+	} = payload;
+	MessagePayload {
+		spec_version,
+		weight,
+		origin,
+		call: call.0,
+	}
+}
+
+pub(crate) fn compute_maximal_message_dispatch_weight(maximal_extrinsic_weight: Weight) -> Weight {
+	bridge_runtime_common::messages::target::maximal_incoming_message_dispatch_weight(maximal_extrinsic_weight)
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
diff --git a/bridges/relays/bin-substrate/src/rialto_millau/cli.rs b/bridges/relays/bin-substrate/src/rialto_millau/cli.rs
deleted file mode 100644
index 841f5427ba..0000000000
--- a/bridges/relays/bin-substrate/src/rialto_millau/cli.rs
+++ /dev/null
@@ -1,62 +0,0 @@
-// Copyright 2019-2021 Parity Technologies (UK) Ltd.
-// This file is part of Parity Bridges Common.
-
-// Parity Bridges Common is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Parity Bridges Common is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
-
-//! Deal with CLI args of Rialto <> Millau relay.
-
-use structopt::StructOpt;
-
-use crate::cli::{HexLaneId, SourceConnectionParams};
-
-/// Estimate Delivery & Dispatch Fee command.
-///
-/// TODO [#855] Move to separate module.
-#[derive(StructOpt)]
-pub enum EstimateFee {
-	/// Estimate fee of Rialto to Millau message.
-	RialtoToMillau {
-		#[structopt(flatten)]
-		source: SourceConnectionParams,
-		/// Hex-encoded id of lane that will be delivering the message.
-		#[structopt(long)]
-		lane: HexLaneId,
-		/// Payload to send over the bridge.
-		#[structopt(flatten)]
-		payload: crate::cli::encode_message::MessagePayload,
-	},
-	/// Estimate fee of Rialto to Millau message.
-	MillauToRialto {
-		#[structopt(flatten)]
-		source: SourceConnectionParams,
-		/// Hex-encoded id of lane that will be delivering the message.
-		#[structopt(long)]
-		lane: HexLaneId,
-		/// Payload to send over the bridge.
-		#[structopt(flatten)]
-		payload: crate::cli::encode_message::MessagePayload,
-	},
-}
-
-impl EstimateFee {
-	/// Run the command.
-	pub async fn run(self) -> anyhow::Result<()> {
-		super::run_estimate_fee(self).await.map_err(format_err)?;
-		Ok(())
-	}
-}
-
-fn format_err(err: String) -> anyhow::Error {
-	anyhow::anyhow!(err)
-}
diff --git a/bridges/relays/bin-substrate/src/rialto_millau/mod.rs b/bridges/relays/bin-substrate/src/rialto_millau/mod.rs
index 6b61653ae3..a04cd55f7d 100644
--- a/bridges/relays/bin-substrate/src/rialto_millau/mod.rs
+++ b/bridges/relays/bin-substrate/src/rialto_millau/mod.rs
@@ -16,7 +16,6 @@
 
 //! Rialto <> Millau Bridge commands.
 
-pub mod cli;
 pub mod millau_headers_to_rialto;
 pub mod millau_messages_to_rialto;
 pub mod rialto_headers_to_millau;
@@ -31,111 +30,15 @@ pub type RialtoClient = relay_substrate_client::Client<Rialto>;
 use crate::cli::{
 	bridge,
 	encode_call::{self, Call, CliEncodeCall},
-	encode_message, CliChain, HexBytes,
+	encode_message, send_message, CliChain,
 };
-use codec::{Decode, Encode};
+use codec::Decode;
 use frame_support::weights::{GetDispatchInfo, Weight};
 use pallet_bridge_dispatch::{CallOrigin, MessagePayload};
 use relay_millau_client::Millau;
 use relay_rialto_client::Rialto;
-use relay_substrate_client::Chain;
 use relay_westend_client::Westend;
 use sp_version::RuntimeVersion;
-use std::fmt::Debug;
-
-async fn run_estimate_fee(cmd: cli::EstimateFee) -> Result<(), String> {
-	match cmd {
-		cli::EstimateFee::RialtoToMillau { source, lane, payload } => {
-			type Source = Rialto;
-			type SourceBalance = bp_rialto::Balance;
-
-			let estimate_message_fee_method = bp_millau::TO_MILLAU_ESTIMATE_MESSAGE_FEE_METHOD;
-
-			let source_client = source.to_client::<Source>().await.map_err(format_err)?;
-			let lane = lane.into();
-			let payload = Source::encode_message(payload)?;
-
-			let fee: Option<SourceBalance> =
-				estimate_message_delivery_and_dispatch_fee(&source_client, estimate_message_fee_method, lane, payload)
-					.await?;
-
-			println!("Fee: {:?}", fee);
-		}
-		cli::EstimateFee::MillauToRialto { source, lane, payload } => {
-			type Source = Millau;
-			type SourceBalance = bp_millau::Balance;
-
-			let estimate_message_fee_method = bp_rialto::TO_RIALTO_ESTIMATE_MESSAGE_FEE_METHOD;
-
-			let source_client = source.to_client::<Source>().await.map_err(format_err)?;
-			let lane = lane.into();
-			let payload = Source::encode_message(payload)?;
-
-			let fee: Option<SourceBalance> =
-				estimate_message_delivery_and_dispatch_fee(&source_client, estimate_message_fee_method, lane, payload)
-					.await?;
-
-			println!("Fee: {:?}", fee);
-		}
-	}
-
-	Ok(())
-}
-
-pub(crate) async fn estimate_message_delivery_and_dispatch_fee<Fee: Decode, C: Chain, P: Encode>(
-	client: &relay_substrate_client::Client<C>,
-	estimate_fee_method: &str,
-	lane: bp_messages::LaneId,
-	payload: P,
-) -> Result<Option<Fee>, relay_substrate_client::Error> {
-	let encoded_response = client
-		.state_call(estimate_fee_method.into(), (lane, payload).encode().into(), None)
-		.await?;
-	let decoded_response: Option<Fee> =
-		Decode::decode(&mut &encoded_response.0[..]).map_err(relay_substrate_client::Error::ResponseParseFailed)?;
-	Ok(decoded_response)
-}
-
-pub(crate) fn message_payload<SAccountId, TPublic, TSignature>(
-	spec_version: u32,
-	weight: Weight,
-	origin: CallOrigin<SAccountId, TPublic, TSignature>,
-	call: &impl Encode,
-) -> MessagePayload<SAccountId, TPublic, TSignature, Vec<u8>>
-where
-	SAccountId: Encode + Debug,
-	TPublic: Encode + Debug,
-	TSignature: Encode + Debug,
-{
-	// Display nicely formatted call.
-	let payload = MessagePayload {
-		spec_version,
-		weight,
-		origin,
-		call: HexBytes::encode(call),
-	};
-
-	log::info!(target: "bridge", "Created Message Payload: {:#?}", payload);
-	log::info!(target: "bridge", "Encoded Message Payload: {:?}", HexBytes::encode(&payload));
-
-	// re-pack to return `Vec<u8>`
-	let MessagePayload {
-		spec_version,
-		weight,
-		origin,
-		call,
-	} = payload;
-	MessagePayload {
-		spec_version,
-		weight,
-		origin,
-		call: call.0,
-	}
-}
-
-pub(crate) fn compute_maximal_message_dispatch_weight(maximal_extrinsic_weight: Weight) -> Weight {
-	bridge_runtime_common::messages::target::maximal_incoming_message_dispatch_weight(maximal_extrinsic_weight)
-}
 
 impl CliEncodeCall for Millau {
 	fn max_extrinsic_size() -> u32 {
@@ -204,7 +107,7 @@ impl CliChain for Millau {
 				let call = Target::encode_call(&call).map_err(|e| e.to_string())?;
 				let weight = call.get_dispatch_info().weight;
 
-				Ok(message_payload(spec_version, weight, origin, &call))
+				Ok(send_message::message_payload(spec_version, weight, origin, &call))
 			}
 		}
 	}
@@ -274,7 +177,7 @@ impl CliChain for Rialto {
 				let call = Target::encode_call(&call).map_err(|e| e.to_string())?;
 				let weight = call.get_dispatch_info().weight;
 
-				Ok(message_payload(spec_version, weight, origin, &call))
+				Ok(send_message::message_payload(spec_version, weight, origin, &call))
 			}
 		}
 	}
@@ -299,14 +202,11 @@ impl CliChain for Westend {
 	}
 }
 
-fn format_err(e: anyhow::Error) -> String {
-	e.to_string()
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;
 	use bp_messages::source_chain::TargetHeaderChain;
+	use codec::Encode;
 	use relay_substrate_client::TransactionSignScheme;
 	use sp_core::Pair;
 	use sp_runtime::traits::{IdentifyAccount, Verify};
@@ -363,7 +263,7 @@ mod tests {
 		);
 
 		let call: millau_runtime::Call = millau_runtime::SystemCall::remark(vec![42; maximal_remark_size as _]).into();
-		let payload = message_payload(
+		let payload = send_message::message_payload(
 			Default::default(),
 			call.get_dispatch_info().weight,
 			pallet_bridge_dispatch::CallOrigin::SourceRoot,
@@ -373,7 +273,7 @@ mod tests {
 
 		let call: millau_runtime::Call =
 			millau_runtime::SystemCall::remark(vec![42; (maximal_remark_size + 1) as _]).into();
-		let payload = message_payload(
+		let payload = send_message::message_payload(
 			Default::default(),
 			call.get_dispatch_info().weight,
 			pallet_bridge_dispatch::CallOrigin::SourceRoot,
@@ -396,10 +296,11 @@ mod tests {
 	fn maximal_rialto_to_millau_message_dispatch_weight_is_computed_correctly() {
 		use rialto_runtime::millau_messages::Millau;
 
-		let maximal_dispatch_weight = compute_maximal_message_dispatch_weight(bp_millau::max_extrinsic_weight());
+		let maximal_dispatch_weight =
+			send_message::compute_maximal_message_dispatch_weight(bp_millau::max_extrinsic_weight());
 		let call: millau_runtime::Call = rialto_runtime::SystemCall::remark(vec![]).into();
 
-		let payload = message_payload(
+		let payload = send_message::message_payload(
 			Default::default(),
 			maximal_dispatch_weight,
 			pallet_bridge_dispatch::CallOrigin::SourceRoot,
@@ -407,7 +308,7 @@ mod tests {
 		);
 		assert_eq!(Millau::verify_message(&payload), Ok(()));
 
-		let payload = message_payload(
+		let payload = send_message::message_payload(
 			Default::default(),
 			maximal_dispatch_weight + 1,
 			pallet_bridge_dispatch::CallOrigin::SourceRoot,
@@ -420,10 +321,11 @@ mod tests {
 	fn maximal_weight_fill_block_to_rialto_is_generated_correctly() {
 		use millau_runtime::rialto_messages::Rialto;
 
-		let maximal_dispatch_weight = compute_maximal_message_dispatch_weight(bp_rialto::max_extrinsic_weight());
+		let maximal_dispatch_weight =
+			send_message::compute_maximal_message_dispatch_weight(bp_rialto::max_extrinsic_weight());
 		let call: rialto_runtime::Call = millau_runtime::SystemCall::remark(vec![]).into();
 
-		let payload = message_payload(
+		let payload = send_message::message_payload(
 			Default::default(),
 			maximal_dispatch_weight,
 			pallet_bridge_dispatch::CallOrigin::SourceRoot,
@@ -431,7 +333,7 @@ mod tests {
 		);
 		assert_eq!(Rialto::verify_message(&payload), Ok(()));
 
-		let payload = message_payload(
+		let payload = send_message::message_payload(
 			Default::default(),
 			maximal_dispatch_weight + 1,
 			pallet_bridge_dispatch::CallOrigin::SourceRoot,