@I know You know
Start by taking those spacers off the truck. They're more liable to cause more problems than the "style" is worth. Especially at 2in thick.
Now for tires. You want to meet or exceed the load rating of the ORIGINAL spec'd tires. This will preserve your tow ratings, payload ratings, and general feel of the truck. As load rating goes up, typically the stiffer the ride (my problem right now). You can get "P-Metric" or "LT" tires. Either are acceptable for your truck. If using P-Metric, lower the load rating by 10%. Forget where I read this, but seems to hold water when looking at various configurations. Lots of other things on a tire to consider. Treadwear, number of plys in the sidewall, things like that.
Sizing works like this........Lets take my 275/55/20 tire as an example. 275 is the "width" expressed in millimeters. 55 is the aspect ratio expressed as a percentage of width. 20 is the wheel diameter. SO, my 275's are nominally 275mm wide (10.826in), however the spec sheet shows the tread width is actually 11.1in. The 55% aspect ratio tells me that each sidewall should be 55% of the width or 151.25mm (5.95in). And the easy one, they fit on 20in diameter wheels. To find overall expected height, you add two sidewalls with the tire diameter
[(2 sidewalls)*(55% aspect ratio)*(275mm section width)]/(25.4 mm to in conversion) + 20in wheel diameter
(2*0.55*275)/25.4 + 20 = 31.909in - we'll call it 32in
Spec sheet says these are 31.8in overall diameter so we got pretty close on this one. Here's a great size calculator if you don't want to do the math yourself
https://tiresize.com/calculator/ Keep in mind that if you go with larger tires your speedometer will be off by the percentage difference between the original size and the new size. Most programmers can correct for this, or if it's a small (say less than 5%) you can ignore it and just know you're speedo and odometer is off slightly. Towing with larger tires puts a little more strain on the rear end and transmission, again, if you're within 5-10% or so it won't be a big deal.
From there, if you're not after increased traction, wear, or a specific set of capabilities, then pick a set in your size that you like the look of, read the reviews, and let 'er rip.
Does that answer your questions?[/QU
Thank you, absolutely!!!