Second print is done. Model is on point now. 🔥
I added explicit supports when printing the case and managed to break the case when trying to remove them. But that aside, the cover fits very nicely now.
If I was going to do it over, I would optimize for "zero supports needed". The part that attaches to the Heltec case would be flat on the bottom. The shell that would cover 5 sides of the battery would have pegs (on top when printing) that would snap into holes on that flat side of the other piece. Not sure if I'm explaining it well, but it makes sense in my head.
However, it's not worth it to me to re-design the case and print a couple more units. I only really needed one case for myself, and I already have two at this point. No sense in digging this hole any deeper. 😂