I personally think this is not going to be great. Here is why. Williams motors chosen, and truck gearing is made for speed. The motors draw high amperage and the truck gearing is such they fly at low voltage while drawing huge amperage. The "fix" or workaround was to wire 2 motors in series, thus reducing the amperage, and splitting the voltage.
What you want to do is put one motor and one controller per unit negating any chance of serial wiring. Finding a BT decoder that can handle that amperage and not fail with heat and time- let alone less than ideal slow speed operation would be the setbacks IMO.
Did you know that MTH trucks and motor mounts fit great into a Williams frame and would be a better driveline- but then you might as well just use an MTH PS1 as a source engine for modifications IMO.
