To set a Trampa VESC to roll to start, all you have to do is connect the pin labeled “power switch” to any ground pin. RTS has worked so reliably on my Trampa VESC MKIII’s that I would say ditch the switch and just use RTS on all 4.
Unless you are losing a lot of energy to heat, a big motor does not produce more power when you supply the same amps.
A 6355 motor at 50V and 30A makes 1500W.
A 6374 motor at 50V and 30A makes 1500W.
A 6396 motor at 50V and 30A makes 1500W.
A 8580 motor at 50V and 30A makes 1500W.
The energy output of the motor is a product of the electrical energy you put in. Size doesnt change that.
What size does affect is the amount of energy that you lose to heat in your motor. A bigger motor will (generally) build less heat at the same amps and volts as a lower motor, and therefore can accept more amps before burning up.
All that to say, 4x 6396 motors are gonna do you fuck all if you are not pushing big amps to them. Otherwise you might as well have gone with 4x 6355.