This morning I built a fixture to help countersink the AEX wedge for the rudder's trailing edge. It's made out of MDF, has a channel to hold the wedge in place but allow it to slide left to right, and contains two small pieces of wedge screwed into the bottom of the channel to provide a mounting position that will ensure that the countersink is perpendicular to the trailing edge. In the photos below, you can see the fixture in use on my drill press, along with a close-up of the fixture, some templates that I made for quick visual reference during the countersink process, and the finished product after all the holes were countersunk,