I also found some pictures of just the arms from sites that were selling supposedly new old stock replacements (for $25 each!

There was enough of mine left to get some basic measurements so using the remnants of mine and the pictures, it was off to OpenSCAD. Not exactly like the original but it had the dimensions and features it needed:
Printed at 0.1mm/100% infill in PLA+:
After a little wet sanding, installed and working!:
Spent the last few nights transferring 10+ reels of regular 8 and super 8 home movies and it's still chugging along.