Hey, I have made those letters on a vinyl cutted out. Then just applied one layer of paint, stick letters over it, another layer of paint, remove the cutted letter and done.
Take a look at this update on a build thread i made, you can see the whole process there.
https://forum.esk8.news/t/outrun-urban-carver-custom-flux-6384-12s9p-finality/50790/30?u=eretron