I would endorse your view of what is acceptable/permissible.
You could argue that what is below the water is open to your own interpretation.
At Balne Moor the default scale tends to be 1/32, but only because it is more robust and things are less likely to get broken. Many in reality are 'stand off" scale. Things do get broken when you tow.
Most of our tugs have bow thrusters etc even if the real subject does not. We have tugs which are built as pure towing machines and others which are finer scale, it's up to you.
The thing is to enjoy it

however you configure it!