I can play bass pedals fast but for not to long being quite tall, I often think that you need a comfortable leg length for rapid pedal abilities, if your leg is too long or too short it can be a draw back for fast pedal lines as you have to support your leg more if its to long, a leg length that lets the foot just breeze over the pedals is best, only other alternative is to adjust the bench height which usually on organs is impossible.

Noel