Originally Posted by alaxfire

Never thought about it, but here is what I would do :

1. put masking tape all the way across both top and bottom of the letters, JUST touching them.
2. mark the tape with the left and right horizontal position of each letter.
3. use dental floss to remove each letter, one at a time.
4. clean up the letter and the paint using 3M adhesive remover.
5. re-apply the letter using 3M thin double side tape trimmed with an Exacto knife after applying to the letter.

6. when done, remove the masking tape.

By doing it one letter at a time, it will be much easier to get perfect alignment by refrerencing the other letters.