Hi!
Great work until now. This is one of my ideas/projects for next....years? But, as a 1/72nd fan, I will start with the Revell little kit.
Apart from scalloped edges of the wing (the straight ones are typical of the N), why you choose to use different colors for under and upper faces of the wings?
Looking at the original photos, it seems that under they are painted "dirty white" as above, no differences between the shade of grey of underwing and fuselage, and very little between underwing and white center of the Russian roundel. Did you find another photo?
Congrats for all the rest!
Roberto