I removed the F-821-1 top skin after locating where I will mount a cooling/defroster fan on the skin. I clecoed the left and right F-8104 skin support ribs to the top forward skin. I was planning to use a longeron yoke on the squeezer for the 6 rivets on each side, but it was a bit short to reach the rivets, so I switched to my “no hole” yoke. I clamped the skin to the work bench so as to stabilize the skin for riveting. The support ribs have a curve to them, but the .032 top skin is flat. So, I decided to start with the center 4 rivets and deal with the ends next. I found it very difficult to get the squeezer lined up on the rivets in order to get a good shop head. I clenched the first rivet over, but left it to hold the rib in position. Next rivet ended up proud. This ain’t fun!! Besides it is at least 100 degrees and 99% humidity in the shop. Took a break to cool off—went back and set all the remaining rivets on each side—two of them set slightly proud and one slightly clenched. I used a side clamp on the end of the ribs to pull the skin and rib together. Set 2 rivets on the right side, one good one on the left side and one clenched. I drilled out all 6 of the unacceptable rivets and squeezed in new ones. All of them turned out ok except on one end. Drilled it out again. This time I used a small needle nose vise grip pliers to hold the skin and rib together—it was partially in the way, so I very slowly squeezed the rivet enough to hold the pieces together. I removed the vice grips and finished squeezing the rivet. I spent way too much time in getting 12 rivets squeezed—got to step up the efficiency!