Lars, welcome to VAF
As to the wiring runs, the RV6 was not as per-fabricated as the newer models, so it is going to depend on how the builder did things.
There should be a wiring conduit behind the main spar, with the tip lights in it.
With any luck, you can add the new wires to the existing conduit.
__________________
Mike Starkey
VAF 909
Rv-10, N210LM.
Flying as of 12/4/2010
Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.
"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."