I like 52Carl's idea of making a stencil and then spray painting. I did this when restoring hubcaps on my '51. I bought vinyl decals from Jim Carter and when I went to apply them, they were die cut out of a strip of vinyl. I ended up using the background strip as a template and it came out very nice. And still is 20 years later. I have seen the Thriftmaster decals on restored engines and they just sort of look like... decals!
Kent