I made my own on decal paper, I bought a couple of sheets of white paper and a couple of clear sheets.
Now to get white letters on black background, I had to use Microsoft office publisher to get a black background, with white letters....that way when I printed, I ended up with a black sheet and the letters won't print (being white), when put on the tug, and laquered it is very hard to spot the decal.
Brian60, you would have to do the same, but match your boat paint colours, would be difficult, but not impossible.
unless you used a different colour that white for the letters, try a "dirty white" for instance?