I'm pretty much done on the planning stages of my TBH's. See the Equipment Forum for the Sketchup File.
My question is what thickness top bars are you guys using? These will be standard 19" long and 1.25" wide. I have them spec'ed out to 1" thick right now but it would be a lot simpler to use the stock the boxes are built out of instead of cutting down 2x4s. Is 3/4" stiff enough?