And not to sound like a dick, because that does, but don't do this to yourself. Take it from somebody who has. You can't buy boots this way. You will think you're happy with just buying boots online, until you get fitted and find out otherwise. Just go into a place with a good bootfitter. They will fit you for a boot based on what fits your foot first, and on the type of skiing you do second. A pair of X-Wave 7's from last year that fit will work better than SPK's that are a size and a half to big.
That said, I can't actually answer your question. If somebody does, use it only as a starting point. With a good bootfitter you won't need to worry about that either. Just go somewhere, and tell them you ski park (or all mtn, or whatever you ski) and show them your foot. Problem solved.