I just bought some Thirty Two Focus Boas...I wear a size 12 shoe, and wound up buying size 12 boots. I couldn't even get my foot into a smaller pair. I wore them around for a few days then had them heat molded. Only made a couple trip out with them so far, but even if they pack out some I think they'll be fine.
Does that answer your question? Probably not...but Thirty Two's seem to take the size variations/packing out into account.