stringreen
For those who are using a mirror make sure you have one that is slivered on the same surface as you rest the stylus, or you will set it wrong.I'm not sure why you say that. Actually, the further the silvered surface is from where the stylus sits, the more apparent any deviation from level will be. That makes it easier to set accurate azimuth, and some stylus gauges are intentionally designed just that way, such as the terrific Wallytractor. But you can set accurate azimuth either way.