I have a 2000 Ford F350 DRW that I've had since 2006. I ran stock 16" E Rated tires on it, but I always felt the capacity of the tires was a weak link in terms of safety headroom. In addition, I believed the 19.5's with higher pressure would make for a more confident ride. This year I purchased a 2014 Lance 1191 which weighs about 5200# loaded and I upgraded to the following through Mario @ www.duallywheels4u.com. I had them drop shipped to the shop that works on my truck and they installed them.
Vision 19.5 wheels, machined, clear coat
•Installation Kit
•Front: Sumitomo ST718 HWY - 2 x 245/70R19.5 14PLY
•Rear: Sumitomo ST918 Drive - 4 x 245/70R19.5 14PLY
•Force Match Balanced
Mario commented that the Sumitomo's typically need little or no weight to balance them but berated my original Cooper choice as just the opposite. I had a little tire squirm through the 1st 1000 miles but after that they are wonderful.
I have the full Monty of suspension mods + the 19.5's + Centramatics, etc., and the combination yields an extremely composed ride. Perhaps the biggest endorsement is the wife test. She's comfortable driving the truck and has commented that you can't even tell there's a camper loaded. She drove the truck on the twisty, winding road down into Zion NP a couple of weekends ago. Chit chatting all the way, carving corners without any apparent stress. When we got into town I asked her how it handled, and she shrugged, "fine no big deal". I however remember the last time we were there a couple of years ago with the same truck, 16" tires and fewer suspension mods. White knuckle driving. She had to pull over and let me drive.

6 x 19.5" Vision Wheels were $1,338
Installation Kit (32 Lugs, washers, center caps, high pressure stems) $100
2 x Sumitomo 245/70/R19.5 14 Ply G Rated ST718 HWY Steer @ 276 each, $552
4 x 245/70R19.5 14 Ply G Rated ST918 Drive @ $299 each, $1,196
Force Match Balanced 6 x 16.66, $100
Commercial Freight from Florida to Phoenix, $402
Total $3688