Try phoning Edgewise before you go. They get swamped quickly, as they tune by hand (and machine). Graham Lonetto is the owner and do-er, he teched for the US team. They are on Mtn Rd, phone is 802-253-8883. Or if you need to call tonight, there's a cell phone too (802-279-4917). they do specialist tunes, and are not cheap!
If they have too many jobs on, there's another specialist tuning shop (it's all they do, and they sell tuning stuff), on Mtn Rd as you are heading up to the hill. I can't remember the name of it, it's in a wooden house right on the side of the road, on the right as you're heading up. It's quite a way up. Hmmm, they might be Today's Edge, ph 802 253-7455.
Failing that, there are the rental places on the mountain, they do tuning etc too.