QuoteUnstepping is not a viable option at this time since the nearest place to do that is over 40 miles away.
Bummer. Did the rigger explain his plan to run the wire up through the compression post then seal it inside the mast? The wiring on Shamrock is in a short pipe, 8"? high, then all sealed with sealer, maybe silicon but not sure. Don't see how it happens, unless the wire is run outside the compression post then thru the deck around the mast step then into the mast. I just mention this because you may not know the rigger's plan and like it. I would expect his cost, labor, to be quite a bit. But then he may have experience with this and have a good solution. I'd want to know before he starts drilling and cutting.
If you really feel the wind instrument is necessary, perhaps wireless would be a good choice for you.
As always, Your boat your choice.
Jim