I've been sitting on this, almost finished for a while now so after another conversation I did a quick finish and scanned it. Actually it was a good thing to do and work with the ideas given. Before I go any farther... it isn't gong to work for a lot of reasons.
One reason is the rear hoop is only tied down by a single bolt. I would have to modify everything to accommodate a side hit. when the buggy's cage was built the builder knew that a body lift was coming and I wanted the cage to be removable so the body could be removable. I also wanted... neah needed foot room on the floor.
The seats are as far back as can be done so the harness bar is C-shaped. This does not really allow for a usable diagonal or X- design that would not be weak (yeah, I know that maybe but the shelf/rear seat it in the way also).
You can just see the front hoop mount here.
The body is going to need at least 4 holes in for the mount w/bolts to work. The pan is tight fore and aft but racking... I'm not sure as I haven't really paid attention to it. The body lift did wonders for flexing and racking but if there is any left I just don't know.
The inner plate that goes on the cage hoop will need to be thick enough to be counter bored to accept the nose of the C-channel mounting tubes (exacerbated in the Iso' for clarity) to lessen the shear load on the bolts on an angled hit.
I didn't show it but an angle iron piece could be added to the upright part of the hoop to reduce flex of the long length but again, the shear is going to be in the bolts at the bottom (he front hoop has two of them per side while again the rear only has one).
I think I am going back to making myself an 18ga plate with bead rolls to strengthen it up. Less complicated, less room taken and maybe stronger. Yes, the bolts are still in shear.
I forgot to thank everyone who made input on this. You don't realize just how much it helped as I got to look at it a lot differently than I originally had. I think the end plan is about the same (not quite for sure) but it did help me clear up some questions that may have come up after I was finished (second thoughts).
Lee