diff --git a/counterparty-core/counterpartycore/lib/backend/bitcoind.py b/counterparty-core/counterpartycore/lib/backend/bitcoind.py
index 5000d995d..f5c2bb17b 100644
--- a/counterparty-core/counterpartycore/lib/backend/bitcoind.py
+++ b/counterparty-core/counterpartycore/lib/backend/bitcoind.py
@@ -116,6 +116,9 @@ def rpc_call(payload, retry=0):
 
 
 def rpc(method, params):
+    # if current_process().name != "MainProcess" and current_thread().name not in ["MainThread", "Watcher"]:
+    #    return safe_rpc(method, params)
+
     payload = {
         "method": method,
         "params": params,
@@ -127,6 +130,7 @@ def rpc(method, params):
 
 # no retry for requests from the API
 def safe_rpc(method, params):
+    start_time = time.time()
     try:
         payload = {
             "method": method,
@@ -144,6 +148,9 @@ def safe_rpc(method, params):
         return response["result"]
     except (requests.exceptions.RequestException, json.decoder.JSONDecodeError, KeyError) as e:
         raise exceptions.BitcoindRPCError(f"Error calling {method}: {str(e)}") from e
+    finally:
+        elapsed = time.time() - start_time
+        logger.trace(f"Bitcoin Core RPC call {method} took {elapsed:.3f}s")
 
 
 def getblockcount():
@@ -432,10 +439,12 @@ def search_pubkey_in_transactions(pubkeyhash, tx_hashes):
 
 
 def list_unspent(source, allow_unconfirmed_inputs):
+    # print(current_process().name, current_thread().name)
+
     min_conf = 0 if allow_unconfirmed_inputs else 1
     bitcoind_unspent_list = []
     try:
-        bitcoind_unspent_list = safe_rpc("listunspent", [min_conf, 9999999, [source]])
+        bitcoind_unspent_list = safe_rpc("listunspent", [min_conf, 9999999, [source]]) or []
     except exceptions.BitcoindRPCError:
         pass
 
diff --git a/counterparty-core/counterpartycore/lib/composer.py b/counterparty-core/counterpartycore/lib/composer.py
index 9707ab935..197f829e1 100644
--- a/counterparty-core/counterpartycore/lib/composer.py
+++ b/counterparty-core/counterpartycore/lib/composer.py
@@ -77,13 +77,13 @@ def create_tx_output(value, address_or_script, unspent_list, construct_params):
 
 
 def regular_dust_size(construct_params):
-    if "regular_dust_size" in construct_params:
+    if construct_params.get("regular_dust_size") is not None:
         return construct_params["regular_dust_size"]
     return config.DEFAULT_REGULAR_DUST_SIZE
 
 
 def multisig_dust_size(construct_params):
-    if "multisig_dust_size" in construct_params:
+    if construct_params.get("multisig_dust_size") is not None:
         return construct_params["multisig_dust_size"]
     return config.DEFAULT_MULTISIG_DUST_SIZE
 
@@ -481,6 +481,10 @@ def prepare_unspent_list(db, source, construct_params):
         else:
             source_address = source
         unspent_list = backend.list_unspent(source_address, allow_unconfirmed_inputs)
+        # exclude silentely utxos with balances
+        unspent_list = filter_utxos_with_balances(
+            db, source, unspent_list, construct_params | {"exclude_utxos_with_balances": True}
+        )
     else:
         # prepare unspent list provided by the user
         unspent_list = prepare_inputs_set(inputs_set)
@@ -827,16 +831,8 @@ def check_transaction_sanity(tx_info, composed_tx, construct_params):
     "unspent_tx_hash": (str, None, "Deprecated, use `inputs_set` instead"),
     "dust_return_pubkey": (str, None, "Deprecated, use `mutlisig_pubkey` instead"),
     "return_psbt": (bool, False, "Deprecated, use `verbose` instead"),
-    "regular_dust_size": (
-        int,
-        config.DEFAULT_REGULAR_DUST_SIZE,
-        "Deprecated, automatically calculated",
-    ),
-    "multisig_dust_size": (
-        int,
-        config.DEFAULT_MULTISIG_DUST_SIZE,
-        "Deprecated, automatically calculated",
-    ),
+    "regular_dust_size": (int, None, "Deprecated, automatically calculated"),
+    "multisig_dust_size": (int, None, "Deprecated, automatically calculated"),
     "extended_tx_info": (bool, False, "Deprecated (API v1 only), use API v2 instead"),
     "old_style_api": (bool, False, "Deprecated (API v1 only), use API v2 instead"),
     "p2sh_pretx_txid": (str, None, "Ignored, P2SH disabled"),
@@ -874,7 +870,7 @@ def prepare_construct_params(construct_params):
         "segwit",
         "unspent_tx_hash",
     ]:
-        if field in construct_params:
+        if field in construct_params and construct_params[field] not in [None, False]:
             warnings.append(f"The `{field}` parameter is {CONSTRUCT_PARAMS[field][2].lower()}")
 
     return cleaned_construct_params, warnings