Late last night (actually early this morning) I drilled all the rivet hole locations up to #19 for #8 screws. I'm going to screw all these floor pans down rather than using pop rivets.

After work, I got started drilling the nutplate attach holes on either side of the #19 screw holes. At the ends of the ribs, I needed to drill rivet holes for the kind of nutplates that have a lug on only one side. Brent's nutplate drilling jig is really coming in handy.