So since the last post I've found out a few things
The PO might have owned a tape measure, but didn't use it well. The triangulated 4 link brackets were off, but after removing the body I found out why. No matter what I measured it all came back wrong. Finally measured the frame diagonally and it started making sense. The frame is racked (3/8-1/2") and all the bracket locations were to try to compensate. Figured it's best to cut it all out and start over, so out came the cutoff wheel and sawzall. When I made the last cut on the center x-member I heard that "tink" sound and knew the frame was under tension. Re-measured and it came back about 1/4", but it went to the body shop so it can be racked on the frame machine and straightened.
Changed direction on the rear suspension as I've always had doubts about trying to run decent HP through a non-adjustable triangulated setup. Going with an adjustable parallel 4 link when it goes back together. The car's purpose has changed a bit since it's become clear street duty will be REALLY limited, so why make so many compromises? Won't turn that well, but now I'll be able to tune the rear suspension to get a better launch.