ORIGINAL: Popriv
How about bolting a straight edge in place of the prop and checking to see if its parallel to the LE of the wing?
I would have to figure out what 2 degrees is but at least there would be something I could measure?
steve
Multiply the lenght of the staright edge by 0.03492; that will be the difference in distances of each tip to the leading edges.
Example:
For a straight edge of 24", with a hole in the center installed like a propeller, the measured distances from the extremes to the leading edges should have a total difference of 0.838" for 2 degrees.