More prep work on the tanks. Both inboard ribs were match drilled to the cover reinforecement ring, then rivet holes dimpled in the rib and countersunk in the reinforcing ring. The reinforcing rings were then riveted with platenuts to the rib. I fabricated doublers for the vent line and fuel sender terminal areas wher I oversized the holes. These were match drilled to the ribs and the proper size hole drilled for the fittings. This should be a very adequate solution. Lesson learned: Use calipers to measure everything before you start drilling holes!!!! I drilled the tank attach bracket, rib and reinforcement on the left side for the inverted fuel pick-up. Lastly, I fabricate the hinged trapped door for the left tank, which traps fuel in the compartment with the pick up during aerobatic flight. This was then attached to the second inboard rib.
