It's not that it's underbent but the weight of the structure itself causes it to sag and spread there. Taking the weight off by lifting at the top of the side skins helps and pushing in from the outside will get you the rest of the way. The awls are great for precise alignment. Once the pans are riveted, this area is rock solid.
Patrick Kelley - Flagstaff, AZ
RV-6A N156PK - Flying too much to paint
RV-10 14MX(reserved) - Fuselage on gear
EAA Technical Counselor #5357