Wassssuuup
For your rear bumper are you going to have a swing out tire carrier? I can't remember if you said so or not?
Anyway if you are, I recomend using this spindal, it can carry the entire weight of your carrier.
The one I used was rated @ 1K Lbs, it's basically a trailer spindal.
My 4xclub's website is down so I cannot post pics of my setup right now.
The main part of my bumper is 3"x8"x6' square tubing. \ cut the left then /cut the right. Before you cap the tubing you can weld up the spindal & frame mounts inside & out.
Anyway food for thought
Burt