yes i don't get the problem also not, in a clutchsystem you can use the dmd controler, wipe out the mechanical speed controler with servo and get the dmd wired to the motors, i did it with a car electronic speedcontroler this is a equivalent of the dmd but it was on that moment the only thing i had on hand
i don't take any space my electronic speedcontroller can take 55mAh more than enough for a tank. It was originaly from my robbe's Testarossa at 1/10