The plans say you should use a 3/16 drill bit as a spacer under the aft spar but I found I needed to increase this by 1/32 to get the forward and aft tooling holes alligned with the rear deck.
I used a rod between the tooling holes, then measured from this to the deck to get 0 degrees incidence
Same at the forward tooling holes
I clamped the ailerons and drilled the control horns
