Stay away from the Sunny tires on a dually they are like hard plastic. They haven't held up to the weight on a F150 we had and side walls come apart.
New Lexani tires are not as good as they used to be, but I have some customers running them in 24s and have only had one complaint with a sidewall crack. Turns out the alignment was off and caused premature wear.
I prefer Falken, Sumitomo, Nitto, Toyo, and Hankook for the heavier load ratings.