Welcome from Rhode Island
Glad to hear you are going to be sourcing more "C" body parts in the future.
I have been using your parts for my "A" and "B" bodies for years.
I think many times, even just to list parts that are interchangeable with "C" / "B" bodies or "A" bodies would be a big help. You would not have to carry any additional inventory. I mention this because recently I needed a heater motor vent tube for my Fury while rebuilding the heater box. only after looking up the part number, did I realize it was the same as my 66 Belvedere and 69 Coronet. Things like various side markers, engine bay decals and engine parts would also interchange. If nothing else, it would give the perception of carrying more "C" body parts and probably more Web hits.