Edge Distance
Jamie,
I have just completed this drilling and encountered the same problem. The HS-405 does not have enough edge distance at the front flange holes. The edge distance is established by the dimension of the prepunched skin and the length of the 405. The only way to increase the edge distance at the front 405 flange hole would be cheat the 405 forward. This is not possible because cheating the 405 forward pushes the 702 spar forward, decreasing the edge distance at the toe of the 702 flange. I called Vans and they said that this minor dimensional issue has existed since the introduction of the -4. They said the edge distance on the 405 is no problem and to continue on.
I suggest placing a center line on the 702 flanges before assembly to verify that the 702 flange is at an acceptable location before match drilling to the skin. Vans documents states that the 404, 405 and 702 should be pulled tight before drilling. This is an important note considering the minimum edge distance on the 405 and the tendency for the 702 to push forward if not clamped.
Good luck.
Robert