I cut the shapes myself from low-tack frisket paper, painted over them and peeled them up. It was my first attempt at that method, so I ran into a few problems. I just used acrylic, water-based paints. The clear-coat is the hardest part.
Masking is super hard. I plug the holes with soft foam and cap it off with tape. I am still experimenting.
Believe it or not, I used gloss clear spray paint. It's a pain, because it dries fast, initially, but doesn't completely harden for quite a while. Especially if you get it on thick enough to look decent. I haven't had any experience with professional grade clear coat. Someday, maybe.