I'd say the ferrules Warmoth sells are most likely to fit the bodies Warmoth sells... and in the grand scheme, (a) they're on the back of the guitar, so cosmetics may not be a primary concern, and (b) they are unlikely to have any discernible sonic difference anyway, except that "I paid top dollar for vintage-correct nickel ferrules, and they sound so awesome" variety of self-deception. I'd say go with chrome unless you're shooting for a vintage-y vibe.
Bagman