Each Character is its own individual blueprint in the book.
I wanted some numbers and letters to use with my city block blueprint, ones that were nice and visible in the map view as well as looked good in person (please forgive the Q, it bothers me...)
The screenshot shows on the left how it looks on the map, and on the right of course how it looks up close.
The hazard concrete is a 9x7 block while the characters themselves are stone brick 7x5. This allows for a nice little border around the characters. I only went so far as having 0-9 and A-Z. I was going to add some characters, but as they didn't have those for the label, I just left them out for now.
Cheers