I would've never thought about the 3rd member having clearance issues on the frame rail with TTB. How much concern is driveline angle with the older GM axles? seems to me it would be worth it to just go driver drop on the T-Case anyway and use a HP D60. I know I'm kind of pushing the limits of the front CV on my K5 at full droop, and that's with leaf springs and maybe 12" up front...
I am binding at full droop. That’s with the cv ground and the yoke clearanced at the axle. I have a lp Chevy 60 though. Rather than buy a fancy high angle shaft, redo the entire suspension. Lol