>>9871827Shapeways is pretty much a scam when it comes to needing anything precision-based. Lego is autistic when it comes to their measurements so having a third party company that has no understanding of what their printing is a surefire way to not get what you want.
Honestly I've gotten a lot of masks from Etsy sellers like Drifting and Buryu and they're really good at making sure they fit on bionicle heads since they know what their end-use is supposed to be.