The hole had to be where I drilled it, as the bulkhead is very thick for strength, and the inside of the pylon has a central channel for wires and a network of stiffeners to each side of the channel. The easiest place to drill is that exposed end, as it doesn't have all that.

I think the string, cut long, tied to a finish nail one one end and the wires on the other, should be enough to get it going.

I just wish I hadn't been so stupid as to glue the nacelles on before I was ready. Once again I screwed up.