This morning I continued with the left wing tip lighting, and got my custom mounting plates rivetted in place. It all went together quite well, and the nav/strobe light fits nice and neat.
I've ordered a couple long AN509 countersunk screws to hold the lights in place, but for now I've just got to use a AN3 bolt.
Left Nav/Strobe light mounting plate rivetted in place
The view from the inside of the left wing tip
With the light in place (the AN3 bolt is temporary, until I can get a long countersunk screw)