Fresh masa corn advice please...

Hi, experienced masa folk.
I'm just about to begin my first foray into making masa from corn, and that's bit of an undertaking up here in Ontario. Anyway, I've got my cal/ lime and my corn, but, wait....
I've just hit upon a how-to post saying that I need to start with corn from Mexico because the maize from outside Mexico won't work for nixtamalization and masa making. Not that it's not as good, but that it won't work.
Any thoughts out there from those of you who know?
I'm feeling kind of silly heh, heh. Don't know what I'm going to do with all these great carnitas I've made.
Thanks in advance for any help.
SW