I disassembled and deburred the baffle and attach angles and aft rib flanges since they were drilled to final size (#30) with the Angles and Baffle. Reassembled everything and clecoed the Tank Skin to the Baffle. Placed the Left Tank Assembly onto the Left Wing Spar and clecoed all 62 Skin holes into the 62 Tank Attach Platenuts previously assembled to the Left Main Spar. At this point Van's suggest that the Spar be checked for any twist with a plumb bob. Everything looks ok and within spec. The Left Tank was removed and all tank skin rivet holes were match-drilled. I started to countersink the Tank Skin->Baffle holes (82 per side). One side is done.