Brief Description: Set and check HS incidence. Angle of attack.
The plans call out using a 3/16 drill be under the HS rear spar to set the HS incidence to zero. Incidence is angle of attack. Here in image 1 you see I only have 1 drill bit, not 2 like other logs I visit. If the forward HS spar is tightened down then it does not make sense to use 2 drill bits. Under the aft spar. The HS is rigid, it will not twist at all, Not at all.
Then you check to make sure the tooling holes are all equal distance from the turtle deck. As you can see I use my 3/16 reamer and taped it solid to my caliper. I didn’t have to adjust away from the suggested 3/16” drill bit. So, clamp the aft end and drill.