IMO, $420 per tire is outrageous.
I'd already be looking for a different brand, dealer or size.

295 /60 /20 = 33.9" tall x 11.6" wide
285 /65 /20 = 34.6" tall x 11.2" wide
275 /65 /20 = 34.1" tall x 10.8" wide
All widths vary slightly by tire brand & width of wheel tire is mounted on.

All "E" load range means is they have a maximum cold tire pressure of 80 psi, 10 ply rating.

LT E rated tires with section widths of 305mm/12.50" or more have their maximum load capacity rated at reduced maximum cold tire air pressure (65 psi).

The service description contains the actual weight carrying ability load index number & speed rating letter.
( it will be after the size marking and look like this - 125/122R )

The load index number tells how much weight a tire can carry at the max rated psi, the first # of the load index is for single wheel, 2nd # is for dual wheel applications, the letter following those #'s is the speed rating.

The heavier, taller & wider a tire is over stock size the more it will effect mpg.

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I have run NITTO's at 65. only got about 25,000 miles out of them though. A bunch of the rig welders working for me are running "Fierce Attitides" by Dunlop. They all swear by them, and those trucks have a bunch of weight n them constantly. More than a couple claim to have 50,000+ miles on them, but they need to be replaced soon.

They are "D" load rating, but seem to hold up to the weight better than expected as most of these guys are towing around there travel trailers with there rigs.

Just put a set of Cooper ST MAXX on my 13 Ram 2500. Seems to pull pretty good in the mud without much road hum!

That got canned (pro comps) dealer was dragging his a$$ and lied to me so I pulled the pin on pro comps. Went with toyo open country AT's. It's a shame cuz pro comp X-AT is the best tire I ever owned for all around use, good offroad, 50,000+, ride and handling second to none, and looked good. Intersting fact: All pro comp tires are made by Cooper tire and rubber company.

Hankook or Nitto.

Check the ratings on both of these for ride, noise and longevity.

I'm on my second set of Hankooks. Great tires.

I haven't found a tire yet that would last over a year on the ranch feed truck. I just ordered the Goodyear wrangler with Kevlar we'll see how long they last.

Nitto hands down I'm on my 7th set over 4 trucks and couldn't be happier.