Here is a little tool that I made up from a verbal description of a tool that a legendary builder used to drill and/or align drive pins on his TWF wings.

Tool basically plugs into the wing tube, and uses the upper pin to set the location of the lower hole where you will drill your wing root for your TWF drive pin.

The way the tool works is simple. The wing rod and the drive pin need to be parallel in all directions. To make the tool, you simply use a drill press to drill two parallel holes at your particular spacing. Enlarge the aft hole to the diameter of your wingrod. Then drill your upper pin such that it will rest on the top skin of the wing when the drive pin hole is in the correct location top to bottom on you wing root.