I am putting small US stars on 1/700 scale tanks and trucks that are the deck cargo on my Victory ship. I painted them with Model Master acrylic olive drab, then put a spot of Model Master gloss clear where the decals go, applied decals, let dry, then overcoated with Model Master flat clear.
And you can STILL see a discolored/semi-shiny area where the gloss coat went down. These are very small tanks, and the spots really show up. Anything else I can try?