For what its worth , in the mid 90s we had dunlop and maxxis , in the heat of summer if the track temp reached 115 degrees or higher we went to maxxis , normally took 8 laps to come in , but when they did , corner speed was very fast , where the dunlop would tend to slow down. I would think track temps would be a factor in tire choice. Which ever tire runs the fastest 20 laps if that is the distance in your main event.
TWR