Mine are coming out great! Thanks for the design! I'm printing the caps with 0.2mm layer and 0.4mm nozzle, PLA. Bottles are done at 0.32mm and 0.6mm nozzle. Lines up wonderful when done. I did use a randomized seam so the defects wouldn't all line up. I find it helps with threads.

OK I ended up making another one by using the bottle's neck as a negative and cutting the thread out of a hollow cylinder. https://www.tinkercad.com/things/cOagp2hYB4C-gridfinity-pill-bottle-lid

I could print 5 lids in a job, but in "one at a time" mode. If the print head moved around then it wasn't quite good enough. Also, had to print in "super quality" mode which is layer height of 0.12mm

Awesome learning experience though.

I printed this at 0.2mm layer height and it wasn't a great match for the thread on the bottle STL. It wouldn't go on straight and could not bottom out.

I found that some medication lids from square-ish containers of 43.3mm/side were a great fit though. Curiously, this printed lid could tighten down on the medication bottle's threads. In short - threads are challenging.