I set out both skins for the Horizontal Stabilizer and used a sharpie to mark the rivet holes that shouldn't be dimpled. Then I took one skin over to the DRDT2 table and dimpled as many of the rivet holes that I could reach in the first skin. About a dozen or so rivet holes had to be dimpled with the pop-riveter die set. What's next? Dimple the other skin, then machine-countersink the spars.