Not entirely sure. From previous experience buying from Japanese sites, youll get a link in the payment request email where you can login with whichever paypal account you want to, the address just has to match with what you gave them when you bought it.
I did as well, but got hit with a backordered email (or at least thats what google translate tells me) with a wait time of 1-10 days. Copped both pairs, never did buy stuff from atmos so Im learning as well
The biggest they go is a 12 from what it seems