You can buy the w1 glue from sunnyscopa by the way, and use ordinary decal paper for laser printer. Just print mirrored and stick it down with the printed side towards the material, then dry a minute or two with a hair dryer after removing the paper, and you can remove the film, then bake it five to ten minutes at 180 degrees C anf you'll have a very smooth result. If you want more relief or deeper black, just add another layer on top...
To work faster, you can also use a paint stripping heat gun, set to low temperature to cure the glue, then high temp to cure the toner. The toner will be ready when it turns glossy. Beware of dust during the final heating, and off course before applying the decal.
Dials made this way are super robust, hardly scratch and are essentially dishwasher proof.
Ad for the brass turning brown. Use Cape Cod cloth to polish, it will form a protective layer on it that keeps it glossy for a very long time, especially when inside a watch.