Brief Description: Attached L-Angles to rear sides
The process I use was line up the L-Angle line near the longeron and clamped the other end. Then lightly tapped the end so the L-Angle mated with the longeron, marked through the skin just that one end hole. Removed that one L-Angle and center punche and pilot drilled it. Put it back in place and clecoed, clamped the bottom end and drilled and clecoed it. Did all L-Angles to that same point.
Looked it over and just lightly drilled and clecoed from the middle out on each L-Angle. All the lines came in to the holes.