The instructions call for creating the FL-0009 drill jig out of some 1/8" angle aluminum, which I conveniently was able to find an old scrap of at the hangar. After a bit of processing on the band saw, bench grinder, drill press, and belt sander I had a nice drill jig completed.
Once the drill jig was in hand, I used my drill-stop cage tool to countersink the four holes in each of the four flap hinge brackets to just the right depth for a flush rivet. Then a final debur of their rear mating sides.
A package arrived by USPS today from Van's Aircraft with the washers and blind rivets that I reported were missing from my inventory. I reported it on the 12th and it came on the 21st, so that took just 9 days, which isn't that bad. I've filed away those parts into their appropriate bags or jars they were missing from so I can easily find them later.