Attached the counterbalance rib to the spar then rivet the counterbalance skin to the rib. Installed the lead counterbalance. Cleco on the skins, rivet skins to the CB skins, spar and top rib. Blind rivet the top rib to the spar.Rivet on the remainder of the skin. I used MK-319-BS blind rivets that ordered from Vans for the areas that are to narrow to squeeeze the rivets.
Counterbalance attached to the CB rib and CB skin
Counterbalance, CB skin, top rib and skin riveted together.