I have been building on a Sig Cub and trying to decide what I wanted to do with the 80" plus wing. I decided to make it 3 pieces with a removable center section. CNC cut plywood ribs and plywood spar carry throughs. The wings are held tight against the center section with 4-40 socket head cap screws through the center section and into each outboard wing section. You can see in one of the photo's the aluminum tube that the cap screw is placed into to guide it into position and then it is secured using a long ball end socket driver. Almost to the cover stage.

JEB