I had never thought of doing it that way, but it sure makes a lot of sense. The issue most of the times is the back lighting on these things. If the colors used are not solid enough (or they let too much light through) it makes them washed out, blacks begin to appear grey, etc. I would think the water slide decals would be too thin to have any significant amount of light block. Putting on the paint as he does might make it a bit better, but not sure how bright a color like red would look. It would be interesting to try it out on a small graphic, like the belly badges on alpha 1 machines.