[Jordan Baker]

If you want to go that route for the lettering. A model train company called "Woodland Scenics" does a pile of dry transfer letters/numbers in different fonts and colours. What I would recommend is to paint the disk the colour of the letters. Apply your letters. Overpaint in the red colour. Then you can carefully use some tape to remove the dry transfer letters. They will act as a mask and you should get some clearly defined letters.