Sounds like you should be running 529 or 571. I think Motive or Precision is your best bet. Even though you have a V6 carrier you can use a "4 cyl" gear with no loss of strength. With those tires and crawl ratio, it sounds like a cryo is a real good idea. Set the gears only slightly deep.....about 17 In/lb of PPL....about 150 ft/lb on the carrier bearing adjusters....and use the recommended BL. You're good to go

This guy, Flexor, has 42" tires and runs cryo/heat treated 571 Precision rear gears for about 3 years now.
http://gearinstalls.com/flexor1a.htm

Flexor chose cryo treated Precisons for the return policy also....he liked the idea of returning from the trail under his own power

ZUK