Gloss is not used so much to hide the decal film but to give the film a smooth paint texture to adhere to, which eliminates silvering. If the finish below the decal is smooth it doesn't matter much if it's glossy or not. For example I painted this tender shell with SEM trim black, which has a matte finish, decaled/Microsol, then cleared over it with matte clear. No decal film. The matte black was smooth. That's the key. I've decaled over flat/matte finished many times without adding a gloss clear coat over them. As long as the finish is smooth, and you use Microsol to set the decal, the film will disappear once clear coated.
