After finishing my rib flange squaring tool (see Tools section), I got back on the rear spar. I had forgotten to match drill the wing skin holes in the flanges of the W-707E and W-707F aileron bracket reinforcement plates for both rear spars. I took care of that, deburred the new holes, and prepped and primed the 4 plates as well as their respective areas on the rear spars.
Aileron bracket reinforcement plates and rear spar prepped and primed.