After some brainwork I finally made a decision where the holes for the fuel return should be drilled. A connector had already been installed in the fuel tank, the pipe turns 90 degres through the rear wall of the wing-locker. Continue through rib 1-4. I use 3/8" OD aluminum tube with 0,035 wall. Grommets are 3/8 ID and holes are drilled 5/8".
