This project brought together universal head and countersunk rivets into one project and simulates how a stringer or stiffener repair would be done. We cut and broke the 0.050 sheet for both stiffener and put it all together on a 0.063 "skin" piece. This was about a half day's work.
Cross section view.
This is the skin view. I'm not sure if my countersink weren't deep enough or if I set the rivets a tad high, but I had to shave just about all them flush.