Hi Kevin
I'm not sure how many letters that you need to stamp. If you have a Hobby Lobby, Micheal's or other craft store nearby you might want to look at their letter templates. You have a variety of letter styles, upper and lower case and in sizes from 1/2" and up.
The templates /stencils are thin and transparent (blue) so it is very simple to align your letters . Now the hard part, You have to hand cut them with a swivel knife and then bevel each letter. A little time consuming but well worth the extra effort if you are looking for a professional looking product that doesn't look like the common stamps that are available.
Kind Regards
Blake