Okay, figured this all out. When I pulled the shutter from the camera, everything worked fine. Reinstalled, and the shutter release would hang again. So it's binding somewhere. Messed with things a bit more, then found this:

The shutter release arm /tab/lever was bent. So when the shutter was tightened down in the standard, the release assembly would bind against the aperture plate. So when I'd move the aperture, it would move the release enough that it would return to zero. And repeat. I bent things back as best I could without completely disassembling it (not gonna happen right now). Working now.
Installed my little 6x6 ground glass on the film rails and checked rangefinder registration. Infinity was perfect. Minimum focus was dead on. Nothing needed adjusting. Very pleased with that. The rangefinder spot still seems contrasty enough, but it's small. Not sure as I need to do anything about it, or can. Maybe an ink spot on the front of the rangefinder but will test first.
Glued down a few small pieces of the leather covering that had lifted. Have added a ton of Bick 4 to the bellows; when the Elmer's dries I'll treat the covering as well.
Assuming everything still tests out okay after everything dries, I'll go walk around Birdsboro tomorrow morning (before the GD inferno starts again, holy Toledo) and test it out.
I'll be shooting/posting some glamor shots in a bit!
Thanks again to all for your help cyphering out the hiccups on this one. I'm remembering now why I spent so much time doing this in years passed.
Scott