I think the first one looks quite nice, actually. Very nice work with the shaders, they seem to work exactly as they should.
Could you post a few from different angles, some that show the tail and the rear fuselage as well as the belly? Also I'd like to see how the normal map looks zoomed really close.
Anyone got any input regarding the size/depth of the rivets, panel lines, and other details? That's important for mentally calibrating what a "good" normal map should look like.
What normal map strength setting does the first image use in percentage? If that's, like, 50% strength then that could mean that one could make rivets for example 50% fainter, then use full 100% setting on your game, and that would give more "playing room" for deeper, larger details. Very valuable info, that.
I'm actually pretty happy about how the normal map turned out in general. I threw in an effect that makes the individual panels of the skin slightly "bulge" outward between the rivet lines and that really shows up quite nicely on the fuselage. I see a few mapping problems here and there, the lines don't join together exactly seamlessly, but I'd say those issues are not high priority to fix, especially in testing stage.
Dents and dings can also be added as desired, by the way. Technically, it should even be possible to use layered normal maps, which could be very useful for weathering or damage details, but I'm not sure if the memory constraints of operating with multiple 4096^2 maps would be realistic.