After a few more revisions, I decided on a final mezzanine arm design. Did some half-assed mockup with the 10" coilovers borrowed from the front, but I'll likely wait until I've got some 14" coilovers in hand to finalize the coilover mount/side plates. The front heim mount area needs some clearancing for better articulation, but everything travels well otherwise.
1998+ Explorers had the combined VSS/ABS sensor in the 8.8, and if you disconnect this sensor they don't shift properly (and you lose your speedo). My 5.0 swap donor was a 1997, so I've got a trans mounted VSS. With the 9" swap, my speedo will work with no issues. Is it fair to assume the trans will use the same VSS sensor for shift point selection as well? I'm somewhat confident that the sensor in my 8.8 was used purely for ABS and nothing else, but I couldn't find a clear answer online. I figured someone here might know from experience.
I could have very easily tested this by unplugging the diff sensor before I ripped my truck apart, but it's a bit late for that. I'm thinking I don't need the sensor, and my life remains easy. Not a huge deal if I end up needing it, but I'd prefer to know so I can have some machining done to fit a tone ring in the 9" center.
Figured out the coilover positioning and continued working on the mezzanine arms. Burned in the main tubes and cut out the rest of the side plates. Bypass rod end is very tight at full bump, but has lots of room otherwise. I don't expect to see extreme articulation with one end of the axle at full bump anyway, so probably a non-issue. Still have to add four more dimples+connecting tubes in the middle section, but I'll likely be leaving the "hook" portion solid.
I couldn't think of a good way to terminate the dimples without ending at the upper corner, and I didn't like how little metal was left behind. Thinking about it more though, I'll have the inner tube 360 welded plus an overlay for that area. It'll be plenty strong. Completely agreed, I'll continue the dimples for the whole arm.