Match drilling the rivet holes for these brackets isn't too hard. I drilled and clecoed the first two holes while the rib was secured to the work bench in the upright position. Then, wth the bracket located and secured in place, I took the rib down to drill it on the bench. The two holes closest to the 90-deg bend in the bracket are hardest to drill. One can be drilled by simply using the 12-in long #30 drill bit that came with my Avery Tool Kit. The other has to be carefully marked and then drilled with the bracket removed. Image 1 is of me using the 12-in long drill bit and Image 2 is of me drilling that last hole that was marked from the hole in the bracket.
Using My 12-in #30 Drill Bit to Match Drill the Inside Holes
Carefully Drilling the Last Hole that has to be Marked and Drilled