While I forgot to look closer for mechanical grounding higher up the chain (will do Monday morning), today I checked the range of the AOSEMs on the PenRe and the BOSEMs on the UIM.  After some rearranging of the AOSEM mounts for ease of adjustment, I was able to line up all 4 AOSEMs by eye seemingly well.  No electronics are hooked up, so I cannot tell better than by eye for now.  I also centered up 2 of the 4 UIM BOSEMs (which were a bear, but do-able).  Being that I can install and roughly align these OSEM stages, the differential roll between the Top Mass and UIM does not appear to be doing major harm further down the chain.

(It's hard to see the magnet centering from the attached pix, but you can see where the CAMs are sitting in the AOSEM adjustment plates for range.)

...to be continued.