Wing incidence can be checked (although not quite as accurate)
by leveling the fuse on a FLAT and LEVEL surface and then measuring from the surface to the center of the leading edge and then from the surface to the center of the trailing edge. Compare the two measurements. Larger measurement at the leading edge = positive incidence. You can transfer the difference in the measurements to paper and construct a triangle using the wing chord measurement where the readings were taken as the base.
You can then use a protractor to measure the degrees of incidence.