Thanks Adam! To answer your questions, I've actually used 81/82/65 on this one. General consensus seems to suggest that the early prototypes at least were finished in 65 on the lower surfaces. This one is a later prototype though, and probably should be 76 on the bottom. However, I used Mr. Paint colours on this one (far and away the best paints for airbrushing I've ever used), but their RLM 76 represents the late war 'sky green' type, which to me wouldn't have been appropriate at all. So, I used their 65 instead, which, if comparing to the Gunze colours, seems to be somewhere in between their representations of 65 and 76. It looks pretty convincing on the model, anyway!
If you're interested, you can check out all the gory details of the build over at LSP: http://forum.largescaleplanes.com/index.php?showtopic=50956.
Kev