After seeing that last picture, you could give this some thought. use only one board and put the 2 back motors to the same motor control board this is still having it in parallel. You most likely would not have to worry about delay to each motor control board and the way they respond delays and such again would the motor control board handle the load. In this case I would make it as light as possible. This is another idea use 1 motor control board use a 1 to 1 transformer to the motors and you would isolate the motors from the motor control boards this allows isolation of the current from the motors. If you need help on this design radio shack here in the state sometimes have little books on designs and circuits for applications such as this a kind of beginners book into electronics. I do not have an electronic CAD any more or i would let you see what i am talking about more. Transformers are used all the time to isolate a circuit from another one so as not to allow feed back or heavy current applications to muck up another board or circuit. Have fun heck I do. It's kind of fun when the smoke is let out and you get to fix it. good Luck, Sniper 67[&:]