Hello,
Anyone have any ideas about what colors to paint the extra turret insides? Thanks!!
I have only been on a handfull of USN warships as a visitor. Based on that experience, I would say use the light gray of the original scheme, RAL 7001.
The official interior color of the Kriegsmarine ships was RAL 9002 (off-white), as regulated by the “Marinedruckvorschriften” (M.Dv.). For paintwork the standard was ABB. Nr. 31 (Allgemeine Baubestimmung), which was part of the M.DV.Nr. 147. A dark grey band of 1m high from the floor was also specified. You can find samples of RAL 9002 in the web, although they seem to be a little dark for me.