Then again I don't see the benefit of doing this. Letting Electrum send your change to a designated change address doesn't make it any less "your wallet's address". It will be highlighted yellow instead of green to show that it is a change address. By using your system, you confuse which UTXOs in your wallet are change and which have come from external sources, making it more likely for you to compromise your privacy by combining UTXOs you wanted to keep separate or combining multiple change UTXOs in the same transaction.