I can tell you size wise, the 275/65R20 is a great size. It's got more height (not a lot) than stock but the same section width. Typically an AT tire is going to have a wider tread block than the factory goodforayears.
You have to watch the tire ratings, a lot of these large tires are LT or Load Range E (Easiest thing to look at the Max PSI of 80).
They're just over-kill on a half ton and they can really hamper the ride quality / MPG (they are almost always literally 8-10# heavier PER TIRE).
My '16 work truck has 285/65R20s all stock and they are stuffy under it. While you could fit em, man, I wish it had a bit smaller and certainly a lighter tire. I'm really underwhelmed with how the '16 does compared to my EcoBoost, especially when towing my camper. I can't help but think a tall heavy tire has a lot to do with that.
