Just some quick rendering tests in Carrara.
The MoI file was saved as an .obj with the number of polyies bumped up a bit.
There are a few not nice surfaces which I may have to take into the Carrara Vertex Room and fiddle with, smooth, do some UV stuff maybe.

This exercise was to help group the millions of bits--drives me crazy, and then, roughly group those into potential shader groups.
Very difficulty to stop parts moving out of place---you will see some that still need to be returned to correct locations.

All the shaders are only preliminary.

Brian