How do you go about doing the level & gyro calibrating your APM when its installed in a Ritewing ZII ?

I spent several hours with a spirit level and a bunch of shims to orient my ZII  to perform the LEVEL CALIBRATION, and I was really just guessing how much pitch up the nose needed for level flight  based on some photos taken of my ZII while I was flying it manually. 

I just can't imagine being able to do the gyro calibration with this style of plane.

I'm sure that mission planner would time-out before I could get the plane into its second position...

I'm currently using APM1.4 hardware in my ZII, but I believe that the process is the same for all APMs.

I would be interested to know what others have done.