With everything dimpled that needed to be dimpled it was time to study the plans in detail to make sure I tape off the correct holes that were not going to receive rivets right now and would be riveted later on and to put the correct rivet sizes in the correct locations. As done before, everything clecoed up and the enjoyment of watching the -4 rivets squeeze with the squeezer. This went smoothly and all of the rivets were able to be reached with the squeezer. As you can see, I dimpled the tip doubler at the outermost holes. The instructions say to countersink here, but after seeing a few others confirm there is no issue with dimpling instead of countersinking, that is the path I chose since the sandwiched material is much stronger than a countersink, especially in the .040 aluminum.Next up is a part I'm not completely looking forward to……