For printing and strength purposes they might be a half disc, but it won't affect there use. Means I can print in the orientation that makes them the strongest.
yep, with ease.
even better if I have the original part to measure from, but I'll draw it from a good set of measurements.
Edit to add, I'd most likely make a few changes to the design to make it easier to print, but they would work in the same manner.
Interesting idea. not convinced of the torque loading of the plastic, but for low torque applications it should work just fine.
clever to allow a split too, so you can get them on and off.