As I continue to experiment and attempt resin molding, and fiddle and tune the 3d printer, I managed to finish a single full usable dice box, in my preferred copper PLA filament. Its not the ideal design (I have a version with a Runelord’s Sihedron Rune in the top), but the lid and base are functional. Note the small magnets that hold the case closed – they work, though may need a bit of padding to make them a bit stronger. Basically, the holes are just a little bit too deep, leaving the magnets a bit too separated. The copper filament is nice, very warm, and the print is smooth (and reflective due to the glass print bed). Warping is non-existent, but I do have a spot or two where either ghosting or gaps came out, all inside and in corners, but none I consider a failure.
My goal is to produce a copy of this box for each of our players in the Runelords campaign. Still undecided if I will use 3d printing, or resin casting, since it is still debatable which is more reliable, efficient and cost effective. After that, I may consider shifting this over more to my Etsy efforts, and see if there is a market for such an item.