The top aft skins were pretty simple although they are a bit stiff and it took a bit of force to hold it down and align the holes. I also clecoed the 656 gussets to the bulkheads but left them “free floating” over the longeron until the skins were on in order to make sure they were drilled in the proper location. Once the skins were on, I climbed in the back and clamped the gussets with C clamps. All the stiffeners and doubler plates were placed in place prior to putting the skins on. I final size drilled all the holes . The upper skin stiffeners were twisted, cut and drilled. This is a weird part in that a center line was drawn and it was just kind of a line up and drill hole by hole until it was done.