If I was building a cage in a blazer today for me, i would use 1.75" .120 wall. This is against most people that you will see or talk to. My reasoning is that I have spent a lot of time now in my KOH/desert car and with correct design and layout 1.75 is fine. Keep in mind I would move stock parts to make sure the cage went together right.
I agree. Cage in my blazer is built with 1.75" x .120 wl. DOM tubing. Not worried in the least about its abiilty to protect me in a roll over.
Cage design is just as important if not more so then material used.