IIRC that controller uses a simple PB + & - contact closure to register the input to the Micro controller IC.
So it would not be that conducive to pot or PWM.
You would have to replace the 2 PB's with an up/dwn pulser, maybe?
I did run one motor off of a A-M-C BLDC controller powered from 240vac and managed to get the rated rpm out of the motor.
Al.