Prosealed the fuel cap flanges to inside of skin. I just purchased the locking caps from Aircraft Spruce...lets hope they fit properly. Everything riveted in place. I did not have to alter the flange to fit the curve of the skin, It was flat against the skin. This is awesome!!!!! I riveted the vent clip to the wrong rivet on flange....I did have to move the vent line clip to the uper hold aftet this picture was taken because I misread the plans. I prosealed the shop heads of the rivets just to be extra sure no leaks come from fuel flange and skin.