I am on the east coast so I can't help with a location. However, I have my fair share of personal experience with canting.
My left leg is a little bow legged. This, coupled with the fact that the race boots I am running are canted a bit to the outside to start required me to have some work done bring me back to the inside. (So the opposite direction as your wife. My understanding is that A-frame is awful common in females)
Anyway, for me the process was getting fit in the shop, trying it out by making binding shims out of duct tape, and then having my soles ground and lifters added. If you go this route, about 3 strips of duct tape on your AFD (and on an appropriate place on the heal) will equal 1/2 a degree. I was fitted at 1* inside on my left and neutral on my right. I have no doubt this is "correct" but for me having my two feet different after decades without canting didn't feel right. I tried 1* on both but that didn't work at all. I have gone to 1/2 on each boot and I am very happy.
I have never tried the Vacuum boot. But, it certainly isn't the only way. That's for sure.
I wonder if the shop has the capability to grind boot soles, or even if they do maybe they just would like to avoid it. I've found that even 1/2 a degree matters so there isn't much margin for error. A little goes a long way with canting.
Another thought is that the boots your wife is looking at aren't a model that can be ground. That's very possibly the issue.
I spend a decent amount of time at Wolf Creek. I am curious what shop you went to?
Finally, my comment about shims is obvious - you can only use the skis on one foot, which is not ideal at all.
Have your wife try the duct tape trick since it's temporary and she can at least see what she likes.