I always wanted to make my own bar risers and even took a CNC machining beginner's class, but just didn't make it that far. Too many different media I wanted to work in. I wanted them to have a very unorthodox logo that said, "Fuck you, I'm riding!". That's some inside humor from the film Idiocracy. Anyway, I would start with 2", and if you make a pair for me too, I'll be your shop slave when I visit. Also account for available additional cable length with handlebar risers, as this is a big part of Rox Riser's disclaimer regarding potential throttle cable binding...
1983 Toyota pickup: total overhaul, preservation-restoration in constant progress...
1987 Yamaha XT600 2KF (German)
STOLEN: RED XL600 in Portland
I do heavy-duty textile repair, upholstery, and design/manufacture bags.