I tried to improve the hook by encasing the microswitch but it worked better on-screen than IRL. Avoid using the current Tinkercad model as it is non-functional (the STL for the previous working version is available in the repository).
I'm considering going back to OpenSCAD to design the hook as I struggle a bit with getting the precision I want out of Tinkercad. Stuff like centering one shape against another seems more difficult to me when you're dragging stuff around vs. doing it in code, but then again I'm a programmer.
I also came to the conclusion that I'm going to design a printable box for the electronics as well. I looked for an off-the-shelf solution that met my needs and didn't find one. There's several options that will work, but for my specific application I have some size and shape requirements and the boxes I could find locally won't cut it. That's OK, because it's fun to design stuff.