Best thing to do with any tire that sit for more than 2 days is to jack them up and rotate about 1/4 to 1/3 of the tire and set it back down. 2 days later jack up and rotate again. Doesn't matter what style/brand of tire, they all develop a flat spot while sitting.
You could mark the tires before every trip with a different colored crayon at the bottom. Bet the blowout will be within 1/3 of the rotation from the mark.