Jochen Hoenicke has a guide for sending USDT (Omni) with Electrum - How to send USDT with Electrum
The same technique will work with Counterparty. The token transfer is encoded in an OP_RETURN message. With Electrum you simply set the recipient as OP_RETURN followed by the correct HEX code (and very important - amount BTC is 0)
Joe Looney has made the library. I used it for CounterTools and Vanilla Wallet.