go over it with a few clean cloths to get up all the solvent.

Have the person who makes the letters lay them out on release-paper backing, so you can put them up as a group, already properly spaced. When applying, use masking tape to position all the letters taping only the top of the letters, then cut vertically between letter with a scissor so you can lift each individually. Before you remove the release-paper to expose any lettering adhesive spray a DILUTE solution of soapy water on the hull surface before permanently placing the letters (to allow you to reposition the letters slightly if needed, AND to allow you to squeegee trapped air bubbles to the edges), then use a plastic squeegee on each letter to affix them. The squeegee will remove the water but leave the letters at least a few days before waxing the area again. The soapy water (so long as it's dilute) will have no long-term effect on the adhesive. I used about 10 drops of soap for a pint.