Towing with a Toyota Sequoia: wheel size question

"This would be my understanding as well, having more sidewall to absorb bumps under a load. I know of people who have ruined rims with low profile tires and massive pot holes."

True story for much lower profile than most trucks/suvs run.
Another common misnomer, especially with this crowd, is that "low profile" 20s on full size trucks are detrimental to their performance.
Generally not the case with 50 series or greater aspect ratio tires.