you know, I don't know that it really makes tooo much difference. I am always amazed at what I see on the trails out there. One year at EJS, I ran into a stock run on fins. this was a run of stock heeps, all with wrangler gsa's and the like, and they went up all with a minimal amount of force.
My thought process would be the softer the compound the better.
I have never run anything but goodyears, but I have run xtragrips, wranglers and mt'rs there. all were successful.
In fact, the vehicles I have always seen do the best were ones with at's with large cross sections