I am working on the RS Models Ki-61-II Kei and just hand painted the prop with white ensign's Japanese red primer. It went on like glass!! I was told by the vendor that it will need some gloss coat for decaling, but if the red-brown primer is any indication this is the best paint I have ever hand painted. Will post pics when the kit is done.
... I came close to buying an FAA Dark Slate Grey but my LHS had Humbrol 224 ...