I was thinking same as wing nut. I believe HV-A, as well as most of the 56th FG bubbletops, were painted in surplus British colors. The underside may have been NMF though. I concur with Don’s suggestion and go with the Alclad products, there’s really no substitute. I have a buddy who foiled a B-29 and it was more effort than it was worth. I think its still in his “on hold” pile.
If interested in the Alclad NMF, heres my P-47N with an Alclad tutorial in it:
http://cs.finescale.com/fsm/modeling_subjects/f/2/t/151736.aspx
Hope this helps,
Joe