Thanks guys. I would be interested in seeing the picture of Brat IIIs belly, Vraciu. I have quite a collection of P-51 photos now myself, but not sure how many good shots I have of what I refer to as the "belly pan" - the center section of the wing bottom - I've left it bare metal, and seem to recall that the fasteners on the perimeter of this section are quite large and noticeable, but can't recall of the top of my head whether that is from studying Cactus' or Fester's super detailed skins, or if I have a photo of it somewhere.
I know what Vraciu means when is says "chalky", and I suspect it means I have spec/power set too low, as chalk is not reflective at all. Also I agree Greebo that the variation in contrast in the bare aluminum is at the edge of "too much" but I was wondering if reducing the contrast here (diffuse map), but increasing it on the spec map would achieve the desired result. My rivets for the painted area of the wing are in a separate layer so its easy to dial back the opacity of them to make them less visible.
It really helps to take screenshots and get feedback. You guys are invaluable, and I've also spotted a few things wrong that I missed despite just staring, panning, staring at it in game, under different lighting conditions.
I also think I want to try an increase the power and env values for the painted nose - I'm trying for a harder finish there - I think what I have looks more like a "satin" finish.