The skin behind the aft spar has to be trimmed to the correct length and a "hat" channel stiffiner must be riveted in place. I started with the upper skin this afternoon.
UPDATE - I trimmed the edge to 1.90" from edge of the spar flange as per the plans. But I am not happy about the distance between the hat channel and the edge of the skin. So I am considering my option. I can not move the stiffiner out further due to edge distance with the rivets. So its either live with it or reduce to skin about 0.10".