[Joey Milia]

1 yes. however you should be carful about how you select tooth sizing. 3mm pitch will be better for the higher speed early stages but 5mm pitch might be needed for the later ones. I'm also skeptical of the benefits over gears. I like belts for the first stage with placing motors, but gears have a far higher power transmission capability for a given size.

2. Bushings could work given the proper conditions, after all vex uses bushings in their ball shifting gearbox. However they could be problematic, the shaft would have to be steel and machined well or ground. Aluminum is a horrible bearing material and a rough surface would increase wear. They also would probably have more slop than bearings and that would increase gear wear. I don't like and wouldn't recommend using bushings over bearings in such applications. I would look into smaller bearings or just not have the whole bearing in the gear.

If the pulley your using is just the thickness of a vex hex bearings you're probably using belts that are to narrow.

I also don't understand why you need hex bearings or a hex broached bushing. Wouldn't having the bushing hex broached defeat the point of it spinning?