Harv - looking at your mounting board picture (nice job by the way), my dash is similar to yours, but smaller. It is at what looks like a similar angle off of vertical, which I guessed to be 15 degrees. I KNOW Ricks instructions say to mount to a vertical surface, but I held my tiltmeter vertically and at a 15 degree angle off of vertical (to approximate the angle of my dash), and at all angles of tilt in the horizontal plane (i.e. the way we read it), there was no error induced by moving the vertical angle of the meter. So...I took the paper off the double sided sticky tape and stuck the meter on my dash. I THINK this is OK, as I THINK I adequately tested the meter at vertical and nonvertical positions before I decided to mount it there, but if I did something really stupid hopefully Rick will pick up on this thread and let me know.