As great as these Coopers seem to be, my understanding is an aired down highway tire with less space between the lugs is the best performer in deep dry sand pointing more to the AT/2.
I keep seeing this w/ regards to highway tires being the best performers in deep sand and I've got to tell you - you've been misinformed.
Deep sand is the opposite of deep mud in terms of off-road traction:
Deep mud requires deep lugs in tires to successfully maintain traction. Airing down your tires in deep mud helps whether you have street tires or mud tires, but deep lugs are the primary requirement.
Deep sand requires you to air down to maintain traction. Deep lugs help, but deep lugs aren't the primary requirement - properly aired down tires are.
So where does this business (often seen) about deep lugs being no good in sand come from? I think it's primarily from people driving vehicles with aggressive lugs that don't realize airing down their tires in sand is the primary requirement. They drive out in deep sand w/ 45psi in their tires, they start to slip and dig and they respond like they would in the mud - they gas it and subsequently bury it to the axles!
I've driven a LOT of sand, pulled a lot of stuck 4wd's out of the sand. I'll take the deepest lugs I can get, aired down (typically about 16psi) and a gentle throttle over street tires any day. The deep lugs will most definitely pull you better through deep sand if they are aired down properly and you don't spin the tires excessively.
I would suggest anyone that believes differently conduct a few google searches on sand tires, tell me how many street tread patterns they see for drive wheels. Deep lugs are your friend in the sand - they just won't make up for failing to air down properly.
PS - I'm a Michelin fan boy myself, unfortunately they just aren't up to par in the off road arena.
David