How many channels is enough?
Not the resolution the refresh rate HUGGGGGGEEEEEEEE difference. Standard RC uses a 50 hertz refresh rate. That's a minimum of .02 seconds after you hitting the joystick on your xmitter to the aircraft actually being able to do anything not to mention encoding and decoding time. Doubling it would turn that into .01 seconds. It's difficult to tell how pilots would react to the difference because it can only be experienced hands on.