Isn't it also true that you want one size smaller boots for a snug fit and the lining will also break in slightly? Maybe I could get away with a 12, possibly a 11.5?
That is mostly true. I would still go into a snowboard shop and try on a few different brands just to make sure. you dont want to buy a pair online then when you get them your toes are getting smushed in. I ware a size 10 shoe but my last pair of snowboard boots were a 9.