Thanks for the kind words. We will probably make this in inventor soon.
We had considered a single wheel. But can't center it because the gearbox is the center of rotation. If we build this we will experiment with removing one of them for sure.
The pulleys are actually 35 chain on the top and 25 chain on the PG motor. We are more familiar working with chain so we decided to stick with that.
The box tube is from
http://www.metalsdepot.com
We don't have thrust bearings or washers. We were hoping for some insight from CD on where they should go and what type of thing to get.