Hey @Mike-Amos ,
As @Rich-O-Brien mentioned, the metal material is a physically correct metal shader. So, there's no accurate artistic control. Rich made a metal library available, and I will also put that in the next release. For complete artistic control, the Disney material is what you want.
I will have a look at the picking bug. Out of curiosity, is the material directly painted on the faces, or is it painted on the object?
Cheers,
Thomas