My whole bicycle is nothing more than a postulated theory.
CSK20 14mm wide torque 40 6 ball bearing
CSK25 15mm wide torque 68 11 ball bearing
I opted to give up the millimeter to get the heavier support bearing:
2 25's side by side may be the hot ticket if you have the room. Width of EVERYTHING is the constant battle for me. My doohickey is 7/8 inch wide.
My reasoning is, pedalling a bicycle is a system that is perpetually yielding. I was thinking about how the torque falls off dramatically fast when you push a bolt past yield.
Guess I'll find out. I will definitely post the results good or bad. It will be awhile though. Big motor/battery upgrade in the works
Dark humor disclaimer: build my design and you will die