ooh - I recognize the impressive soldering skill demonstrated in that photo (it's mine!).

Ocracoke is spot on. The RX power rails are shared, so you only ever need to supply power once, then the rest just need signals. You just cut off the power wires of the channels that don't need them.

I dunno about using resistor braking - I don't like the thought of things getting hot, so I never tried it. I know what you mean, though - that thing where you attach a resistor to bring the motor to a faster stop once voltage is removed, or something like that. I'm at work, so my google-fu is weak.