I agree with Graybeard on a 350 being big enough.
I've had 3 ATV's ranging in size from 350,425, and now a 700.
The 350 and 425 hauled some heavy loads in their days and rarely did they stop unless it was a steep incline. Only once or twice I had to hand winch (come-along) the 350 and trailer up about 20 feet on a steep incline.
The 700 is definitely overkill and it will wheelie over if you crack the throttle with hardly half it's rated rear capacity. I have not flipped yet and don't plan on it. So the 700 will haul the trailer up the steep incline but I run the risk of flipping if I give it enough gas! What did I gain? Oh well... it was an upgrade from a freak accident lawsuit settlement my wife got. (Some guy had new tires put on his van and made it a mile when one came off. Smacked her and broke a couple bones)
I'm sure the 350 will handle 99% of the stuff you throw at it.
Corn feeders being hauled out 10-09-06. Good thing I got them out to when I did.
Already had 3-6 inches of snow at my shack.