Hooray, it works in PLA!
Printed using my Monoprice 3D Mini (Malyan M200) using the very nice Colido Filament. I had to scale it down to about 75% so I figured the tolerances would be way too small. Apparently not :)
It took a while before I realized which parts were just there for support. The thumbscrew immediately moved, and the main claw just needed a firm push with the thumb to snap loose from whatever was holding it.
Great success, thanx barspin!