I found a font that i really liked, it was not that easy to create the numbers for stained glass, but I did here, showing two versions with color, and a black and white version for you to see if you want to try it out.  The numbers are all "square" at 2.5 inches, but of course that is way too small to make these numbers, so a print shop (or i can as well) needs to enlarge the pattern file to the size you are confortable with.  If you have a transom that has several numbers, these will fit together side by side.