When I mounted the compass on my AI's cockpit hatch, I failed to take into account the fact that the hatch is not mounted in the center of the hull - it's offset to the left by about 1-1/2 inches. So, in addition to having less accuracy when using the compass for a heading, my left leg bottoms out on the compass head when using the Mirage Drive.
I plan to move the compass over by an inch or so. In the meantime, I thought I should mention this so anyone else contemplating mounting their compass on the hatch can take this offset into account.