Trimmed flange on tank channel (7V11-2K) to fit uo to rib # 1 so it is not touching. Laid out rivet pattern on Tank Channel Angle, drilled & clecoed angles to Channel. Note: Placement for Tank Channel (530 mm top fange) was measured straight across from top of Channel to leading edge of Spar Cap (incorrect). Measuring straight across has an error of 5mm to far to the rear. Must be measured from leading edge of Spar Cap along curve of rear rib to 530 mm. Bottom measuremewnt is 525 mm straight across, this measurement was ok. Must fabricate new Tank Channel Angles so Channel can be moved forward 5mm. Primed all (mating surfaces) rear-channel components with Zinc Oxide.