The directions for the E-01402 elevator trim cover plate say to machine countersink the #040 holes. The material is not really thick enough. I tried to countersink it, but it came out horribly. Elongated holes. I belatedly realized that I should have used another piece of material behind it to keep it centered. Even so, the rivets sit a little proud of the plate. It seems to me that these holes could be dimpled, as well as the E-01409-L & -R Servo Support C-Channels. Has anyone dimpled these holes and the C-channels?