“How do I know if these are the right size? Specifically, how much room should there be in the front by the toes? If the arch is in the right place and my big toe isn't hitting is that the right fit even if I'm able to wiggle all my toes up and down a lot? Maybe it's good not to be too snug at the toe but how much should I be able to wiggle my toes and at what point might the boots be too big and I have to go down 1/2 size?”
Flex both feet. If the boots are properly sized, you should be able to feel your toes in light contact with the inside front of the boot.|Walk around the for a few minutes, paying attention to any hot spots, rubs or pinches. Touring boots in particular are sized rather like hiking boots, so if you're not comfortable walking around in them for a couple of minutes you probably won't be comfortable skiing in them for any length of time, either.