What is your level of fab experiece, and what tools to you have? (Big items here are do you have a decent welder, and a bender?)
Easiest is to just buy a pre-fab front hoop, which isn't too much from 4wd/quadratec, which will tie to the stock rear bar.
Then fab up supports from the frame to the cage, mounted correctly with dissimilar sized plates, and bushings/isolators of some sort.
Tube size would be to match the rear of your stock cage, its probably 2" x 0.120" HREW.
If I was going with a fully fabricated cage with a good bender, I'd use 1.75 x 0.120" DOM mild steel(not chrome moly).
ALthough I've done my trucks tubework with 1-1/4" Sch 40 structural tubing, which is 1.66 x 0.140 wall. Held up just fine to my rolls in tellico(one hit hard, one was a soft flop), and other trail damage.
My Jeep, I'll use the DOM, if I ever get around to building it.