Update #1
Text print quality testing and tolerance examination (also ran it with a second piece cloned of the first, quality seems OK for text invisible to the naked eye
I also found that it would fit teensies! Doesn't even need an adapter, though a small piece of plastic would be good to do the trick.
The entire assembly relies on the presence of small tabs that hold the small box together. Everything is pretty rounded so the chance of impact damage is pretty low. The shell is currently PLA and 3mm thick. Would ABS do better for quality? IDK, but I heard it does better for impact resistance.
I also took ANOTHER half a dozen hours and further set about improving the designs. It's drastically different now but still uses the same principles. Maybe I should use magnets? Maybe I should migrate the tabs to the other half?
Who knows? You guys have the say