Guys on TBN have raved about Carlisle AT101s. They only come in bigger size. The local tire outfit ordered one like the sales guy has on his own mower that is similar to the AT101s but will be 3/4 inch wider and higher then the Ryobi's 18x8.5-8s. He wants me try it out for size. I needed another wheelbarrow tire. They're replacing it for me.
I ran AT101's on my 797. Great tire, R1 type lugs, never got stuck again in a wet ditch with those. All you have to do to keep from really tearing up the grass, in a turn, is to keep the inside tire just barely moving.
I bought a Kubota ZD326 recently, and I am thinking of trying the Versa Turfs in 26x12x12, this time around. It currently has just normal old turf tires on it, that absolutely suck.