For what it's worth, I am not sure if the lower 1/3 co witness mounts work with this technique. I have an absolute co witness mount and when looking through irons, the dot sits right on top of the front sight post. I am aware that Aimpoints are virtually paralax free, but I am not sure how that applies to initial zero with a lower 1/3 co witness. I am interested in the answer to this question, so please let me know how it works out for you.
"There is nothing like the hunting of man, and for those who have hunted armed men long enough and liked it, there is nothing else>" Ernest Hemingway.