nit: output value is exactly what's available in the input for confirmation

src/silentpayments.rs

@@ -73,7 +73,7 @@ pub fn create_transaction(sp_address: SilentPaymentAddress, sp_wallet: &SpWallet
 pub fn create_transaction_spend_outpoint(
     outpoint: &OutPoint,
     sp_wallet: &SpWallet,
-    recipient: Recipient,
+    mut recipient: Recipient,
     fee_rate: Amount
 ) -> Result<Psbt> {
     let available_outpoints = sp_wallet.get_outputs().to_spendable_list();
@@ -96,6 +96,9 @@ pub fn create_transaction_spend_outpoint(
         return Err(Error::msg("Not enough available funds"));
     }
 
+    // update the amount for the recipient
+    recipient.amount = total_available;
+
     // create a dummy commitment
     let mut buf = [0u8;64];
     thread_rng().fill_bytes(&mut buf);