I recently replaced my steaming/deck lights with LEDs from Bebi in Fiji
It wasn't working and being 20' up the mast I just could not get at it. Took a rigger (thanks Chris M.). I am not planning to do it again soon.
Bebi recommended (if I remember correctly) was that all joins be soldered, protected with liquid electrical
tape and covered with heat shrink (with the comment that all other joints eventually corrode and fail).
The lights work now, but the real test is time...
I would happily run wiring on the outside of a wooden mast (I've done it on my wooden "radar arch" - so far so good) using tinned wire. If I was being totally obsessive I'd put some thinned epoxy
resin in the holes and allow it to set before screwing. It is more vulnerable to mechanical damage though (found through rigorous scientific testing).