Just a single rear wheel 2500HD, but ran the OEM 245/75R16 Bridgestone E-rated street tires, 265/75R16 Trxus MT D-rated, and now 285/75R16 BFG all-terrain D-rated. I tow my 1-ton K5 on a 2,500 lb. trailer, so total load is around 8,500-9,000 lbs.
Keep in mind that there is more to the load capacity then just the letter rating (C, D, E, etc...). The size makes a difference to, for example a D-rated 285/75R16 has a higher load rating (the actual XXXX lbs. per tire) than an E-rated 245/75R16. I've had people argue that my D-rated 285's with a load capacity of 3,200 lbs. per tire would explode and kill a bus full of nuns if they just looked at a trailer, while the E-rated 245's that were only rated at 3,000 lbs. per tire were perfect for towing
I got a great deal on the Trxus and thus the only reason I went that aggressive. You could definetely feel the tread squirm in the corners as they weren't as solid feeling (caught my attention the first sharp corner after install) but quickly got used to them. Never notice any major difference in handling or comfort when towing the trailer.
The BFG All-Terrains handle a little better, and are way quieter. Again no real difference regarding handling or comfort whent towing.....do notice the slight loss of "power" due to the larger size.