Sway is a function of not having your trailer loaded correctly. While a tow vehicle with a longer wheelbase, stiffer suspension, and stiffer tires does make a difference, a trailer that is loaded correctly will not sway.
Now if you have a tow vehicle that lacks the payload to properly load the trailer, then you're going to be on the edge of stability the whole time. That's why those of us who have been doing this a while insist on a heavy duty pickup and a lot of tongue weight (plus excess for your extra gear and so that if you have any extra weight, you can focus it on the tongue).
While in theory, a good 1/2 ton truck will probably pull 8k pounds okay on an occasional basis, if I knew I was going to buy a travel trailer that heavy, I would buy a 3/4 ton truck. And while the manufacturer of the Tundra might tell you it can pull 10,000 pounds, I think that would be cheating death the whole time, especially because with the limited payload, you're going to have to keep the tongue lighter than you otherwise would.
Weight distribution has nothing to do with sway. Sway control is a band-aid for a trailer that is on the edge of stability. With the right tow vehicle, you will be able to load your tongue heavy and your trailer will never misbehave again.
Or you can go to the ultimate tongue weight increaser.....the 5th wheel.