Mine's easy enough to read, it's 0-100. I can tell going down the road if it's at 38, 39, or 40 psi (the only settings I run, usually it's at 39 unless it's really cold or hot out).
If you're setting it under the hood with an AFPR, simply use a test guage set, they're 0-100 psi in large readable increments and plug temporarily into your schrader valve to get a reading.