may also be controlling factors. An other, earlier thread posed the question of who's responsible when the aircraft hits something while being towed---tug driver/captain-pilot/wing walker?
IIRC there was lots of discussion but I don't recall resolution. I did learn that "one size (tug) fits all"--i.e., can move any size craft, 747, 737, 219, A380?
I recall however description of a towing device being recently approved and that could be controlled from the cockpit, eliminating any other intervention, and placing authority squarely in the hands of the person on the flight deck.
Somehow Airbii and Delta hang in memory... YMMV