THat's a good price at Kirk. Thanks for the info.
I guess it's pretty similar to using a horizontal level when hanging a photo or something on the wall. As long as the bubble is between the two lines as much as possible, then you should be OK.
One would hope so ...
Unfortunately things are not that easy. It all depends on the accuracy of the device (vial and enclosure, even electrostatic charge can play a role) and the reference/mounting base. These 'hotshoe' mounted levels are not that accurate to begin with, and the mounting leaves a significant amount of play and thus inaccuracy.
Of course one can estimate the overall bias by checking the difference between two 180 degree opposite readings, but that doesn't solve the low repeatability of a reading.
But then, even with an accurate device and a repeatable mounting, how rotation-free is your sensor mounted?