I have been thinking of this idea for a while, I think Using a cheap servo tester, and mount a lever on the potentiometer.
I also have one of
these motors- already with a reduction box on it (50:1 iirc)
Should push a 20in bmx bike pretty decent on 6s.
Benjamin White
R/c Monster Team Driver
Jq the car, LST, Sportweks turmoil pro
Unconventional Techniques, Superior Results