Hi there,
This is Bogdan from Romania.
I'm a mechanical engineer - specialized in the industrial robotic field, 3D designer and modeler (from time to time and some projects I could make the functional prototype too).
I'm doing product design, industrial design, reverse engineering, ideation, etc.
I have over 15 years experience working on various systems/devices across multiple industries, from concept to launch.
1 - i will rather go with a hinged type instead of a pivot type lid... (better, stronger, nicer, etc)
2 - for a good print, the minimum wall thickness is 1mm (even the printers could go till .6mm...)
3 - the wallet should have a release mechanism...
4 - i would recommend having a customized plate which to attach to the wallet instead of customizing the lid (will give you the possibility to have a wider range of combinations and a better cost management)
5 - another possibility is to have the base molded/cnc milling or 3d printed, and the lid to be from stainless steel sheet, bent accordingly with the base and serving as a closing mechanism too
Regards
Bogdan