You wear a 12 or a 13 depending on sizing?
Something is very wrong there. You should never be a full size off, maybe you are leaving too much room in your boots. Your toes should touch or push up against the end of the boot when you buy them brand new. If you are doing that there's almost no way you could find a brand that is a full size different and still fits properly. Make sure not to leave any space in the toe box, you will get some space as the boots break in and as you bend your knees in to your riding position.
The Kaiju are great. You can try on a pair of nike sneakers, make sure they are too small, meaning your toes touch the end, and that's your size.
Or you can call someone like Milosport (1.800.675.6134) and they could measure a Kaiju for you but it won't be as exact as the previous suggestion.
It's a great boot. Buy a pair online from Milo or somebody and exchange them if they aren't snug enough. It's not that big of a hassle.