I used my new tungsten bucking bar to rivet the top of the aft skin to the spar. Worked great. It is small yet dense. I was able to reach over the skin and do the whole row. You can see the bottom of the skin is held open by the wood of my holding fixture. Oh, did I mention this is my horizontal stabalizer fixture trimed down for the aileron. I then squeezed the rivets of the nose skin to nose rib, per plan.