Hey Derek!
If you have a hobby store near you that has a decent model railroad section, look for dry transfer model railroad lettering. It comes in little packs for about $4.00 which come in black, white, gold or silver. You should be able to find 6 mm letters. If you use them straight out of the pack NEVER apply them directly from the sheet itself. Letters should be individually cut and then one edge tacked in place with clear tape before burnishing.
Since they can be a little fiddly to align on non flat or irregular surfaces, I sometimes apply them to a clear water slide decal film first. This way the entire lettering panel is easy to slide into the correct position. You can of course apply each letter individually. Always apply water slide decals over a glossy surface so you may need to spray a gloss coat to the area first. Slide them in position and set them with decal solvent. A satin or flat clear coat finish over the whole hull will set them so the decal film disappears.
Another method I've used is to to apply the adhesive vinyl letters that office supply stores sell in packs. You can either use the letters straight out of the packs or if you need a special colour then spray them the colour you want before removing them from the sheet. They do a passable job but are often too thick to be realistic (unless you want raised lettering). The method I prefer is to first spray the lettering area with the letter colour you want. Make sure the paint dries for 24 hours. Always use a masking tape guide to make sure your lettering is in a straight line and apply vinyl letters on the flat tip of an Exacto knife just touching the sticky side so you can joggle the letters straight. Never be satisfied with a crooked or incorrectly spaced letter. Before applying each letter just push it momentarily onto your forehead to reduce the adhesive so theres no risk of pulling your background colour off. Once you have applied all the letters mist a clear coat over them to seal the edges and prevent bleeding. Then spray your hull colour. When it's all dry, peel the letters off carefully and you will have a perfect painted lettering job. The same process is good for waterline stripes which can be found at the automotive stores.
Good luck, send us pics of the finished result.
PJ
Victoria BC Canada