Here are a few alphabet charts you can use to sign your work. The heights assume you are using mixed upper and lower case; less space is required for all upper or all lower case.
Now that my wife has had the time to work with [SQ Stitch] she is absolutely delighted and cannot believe that it was free. She says her work rate, with the help of the software, has dramatically improved as has the accuracy of her stitching. The software has so many useful options to help the user and is very user friendly.....even l can understand it!
The Annunciation Follower of Rogier van der Weyden