I reached a bit of a milestone last night. I finally was able to complete repairs on the broken passenger side strut mount, got the gusset added, and actually have the car so it sets on all fours for the first time.
I'm using Beadalon crimp tubes (necklace-making item) which serves as the bushing inside the upper strut mount. For the moment, I've got a straight-pin holding everything together up-top, with it extending down through the strut and lower A-arm wishbone mount. I added tubing back at the firewall to tie the top of the upper strut tube into the frame rail, which you can see in this pic. It keeps the rear of the resin "tin work" from floating and makes the front end assembly much more rigid.
Head-on shot
Head-on low-angle
Same angle as pic 1 with the tin work setting in place
Passenger side angle
Angle from other side
Comments welcome!