There is a lot of new posts so I'm going to quote this one then add my thoughts.
First off, thanks for the explanation. That and the multi-colored lines. It makes it a lot easier for my feeble mind to understand. Haha! I think yours may be more accurate than mine because I didn't have a good alignment when I did mine, plus a lot of other variables.
I also found that the RC raised with a taller spindle, up from stock, to F-body then F-body with a Raised UBJ. What is happening is the effective swing-arm length is shortening, so the line intersecting the center of the tire and the Instant Center of the swing arm is at a steeper slope so where it intersects is higher at the same distance (center of tire to center of car). This is also shown in your stock setup in the opposite way. I would be curious if you could run a lowered stock spindle with the LCA pivot points stock and the performance tire. My guess is the RC will be even lower. On the other hand, the camber gain will be less as a tradeoff. In my calculations I got -1.04 */in of camber gain with the stock spindle and -1.66 */in with the F-body. I would think an added length UBJ without a corresponding movement in the UCA position would be a bit too much camber gain for modern performance tires. I was planning on using just the FMJ Spindle and doing testing from there for tire temps.
As far as anti-dive: The main reason the factory used a lot of anti-dive was to counteract the soft spring rates and tire sidewalls of the time causing excessive dive under braking. For most practical purposes the downsides of anti-dive is potential bumpsteer/caster changes and lack of driver feel (it doesn't dive under braking at 100% anti-dive so it is harder to feel the weight transfer). The upsides are: It doesn't dive. So in most practical situations it is a net plus because you can run softer spring rates for grip and not dive as much under braking and upset the balance or geometry. You just set it to somewhat less than 100% (80% seems a common recommendation). The one time you don't want it is mostly on circle track cars when you want it to squat before entering a turn and stay down to lower the effective CG through the corner. The cool thing about using a more modern adjustable UCA is you can use the eccentrics or shims in our UCA to set the geometry, then use the UCA to adjust your alignment. If you want to learn more here is a pretty good read: Anti Squat, Dive and Lift Geometry – Geometry Explained Suspension Secrets
Overall, the main problem with suspension geometry is it is like anything else: Full of compromises and everyone has a different opinion of how to do it right. Even something like NASCAR where the racing is very close, the teams can have drastically different ways of getting there.