I have decals on the turret of my tank that I want to protect from overspray with white because I’m contemplating a winter whitewash as the final coat. My first instinct was to put a bit of Tamiya masking tape on the decal but obviously that will rip it off. I’ve seen decals crack and break off with even less molestation that masking tape.
No ideas there…I would paint first decals last
Protect the decals by spraying on a layer of Future, or other clear. After it has cured, you should have no problems putting Tamiya masking tape over them.