Actually, I've been searching for pictures or drawings of the setting I had in mind, but couldn't find any. Obviously, you are right, and the roundels will have to go ...
And this is the time when those modellars magazines with camo shemes and decals are come in handy. Not that I' ve used them anytime.
But most of the time they are useless and overpriced
Citadel paints are any good?