I appreciate all your help on this. It looks like I've got some revisions to do and some additional testing.
I saw some other things that I'm going to attempt with your setup - hopefully I'll be able to toss the revisions out there for you guys if they pan out.
I had run into another guy using thin film resistors, like a 2512 (imperial) surface mount package in order to do his own strain gauge PCB. I'm hoping that once I can get this up and running and understand the circuit a little better - to replace the meandering traces on the PCB with a set of these. This (theoretically) should open up some board space for mounting some other hot ends (Slice Mosquito, E3D Chimera, etc).
We will certainly pass the changes back upstream if we're successful!
By chance do you have an updated BOM for the SmartEffector? I'm about to order some parts on mouser, and would like to try to iron out any discrepancies in my version.