I tow on 7miles of beach, soft stuff.
I have a 2500 SRW, but not a 5th, just a regular hitch TT.
But it's all the same.
The taller and wider the tire the better, and airing it down makes all the difference.
A wider tire makes sense to most people for width, but the taller the tire - when aired down makes a longer front print as well. The bigger the front print (width and length), the lower the contact pressure on each square inch of contact = better floatation.
The taller the tire, the more sidewall = more marshmallow effect = better chance for more flotation if the tire sinks deeper. And the more ground clearance, when aired down. In the really soft stuff, when I was aired down for towing, I would drag my pumpkins in the sand with the stock tires. No longer a problem with the 33's.
I used the stock tires till they were bald.
I aired them down to 12lbs in the front, 9lbs in the back and the trailer 20lbs all the way around. At 12lbs, the front tires were almost on the rim. Never lost a bead.
Never got stuck. But would have if I wasn't aired down soo low. Many others did that were too conservative or lazy to air down correctly for the condition.
Besides towing my TT, 8ft bed was filled with Firewood and 50 more gallons of water, and everything else the family wanted. TT was filled with 35gallons of water and food and everything else for a week on the beach.
I went from the stock tires to 305' (33x12) , air down to 15 front and 12 rear when I towed, and 25 and 20 when not towing. Night and day difference even with the 33x12.
I had a '80 yota with 33x12's (not towing and only a 3800lb truck) , and got 60K miles out of a set of BFG MT, ran them on the street and beach at 17psi all the time. Only for the most powdery dried fine sand did I need 4 wheel drive.