We put on the upper counterbalance rib and skin, and put in the 6 rivets from the skin to the rib.

Here is another picture of the skin and rib, before we put in the rivets

I then dimpled the skins common to the ribs and spars.

The skin was too thin to get some of the holes dimpled, so I clamped an aluminum angle to one edge to help hold it. This worked great

Cleco'd the skins to the skeleton, before putting in the rivets common to the skin and counterbalance skin

Here is the counterbalance weight bolted to the rib. Even though the grip length is right at a -10, there is still a whole lot of threads showing above the nut. I put 3 washers and there was still 6 threads showing. Yet the non-threaded bolt length is not showing above the hole. I think it is ok, just the style of these countersunk bolts, but I'll ask on the forums just in case.