The 6-point cage kits are 1-1/2" x .095 (some say ".090", but it's the same tubing, both numbers are within spec for the tube)
CREW. Not DOM. For your play bug that is just fine and dandy.
Marc...You're seriously confusing HREW with CREW. HREW (Hot rolled) looks like angle iron on the surface ...dark blue gray to blackish with rough texture. CREW (Cold rolled) is bright shiny silver and smooth with a dark seam along one side. CREW is FAR stronger than HREW. HREW is for stuff like wrought iron fence. It's not even strong enough for use in chain link posts and rails. I see this mistake often in forums. Neither is nearly as "Stiff" (let's not confuse stiff with strong) as DOM which has 2x the carbon content of common 1010 CREW. 4130 has 50% more carbon than DOM. Carbon makes steel stiff. But yes...Keep the seam on the inside of bends.
Lee, it wasn't me who said that. The cage OD and wall thickness rules for offroad racing are based on consideration of the wall thickness variations which happen when tubing is formed into such a structure, and took into consideration input from SCCA, NHRA, NORRA, SCIDA, SCTA, NASCAR, USAC and others. Since the original SCORE roll cage rules were written in my dining room by my dad with Mickey Thompson and myself present, I say the above for certain.
My old HiJumper race buggy was made of 1010 CREW and bent with a muffler shop type bender similar to a HF bender, but hydraulic. It got quadruple endoed while flat-out in hi gear in 1984. It's fine still. I have NO issues with using CREW for cages in offroad bugs and buggies.
For a convert which has substantial rust issues and will be offroaded, even if not too hard, I suggest tubing from the front beam to the rear torsion. Set the 6-point A and B pillars on top of the bottom rails. Especially with a +6 beam which has a lot more leverage on the stock pan mounts than a stock width beam. I've seen lots of light play bajas with bent wider beams.
"I wasn't jumping it or anything!"
Then make sure the motor mount frame horns are supported to the cage. I broke them on a mostly street Baja. Since the rear tray is rusted out, the back end of the cage resting on air isn't going to be very effective. I suggest tubing from the ends of the torsion housing up to the rear braces of the cage and down from there to the ends of the forks.
You can see them some painted blue here:
You can build all that with 2 sticks of tubing. Maybe another stick for custom front and rear bumpers.
Be sure the doors are in and you keep trying them as you build it so the doors don't jam when it's all welded. Maybe even wedge the door gaps a little extra wide at the tops. Gusset between the body and cage at the A and B pillars after the cage is otherwise done. The gussets at the A pillar help with the door sagging after the front 1/4s are cut.
Oh, while the rear tray is out, think about leaving it out (not good in mud) or better...make a replacement that's a hatch. Mine is a small hatch for access, but you have the opportunity to go big.
Open:
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At least I said I thought... 
