I'm approaching 12K on my Michellin XPS Ribs. I just returned from 500 mi r/t to west Texas, and before I left, all 6 tires were at exactly the same pressure (76 PSI @ 50 F), after sitting for a month. No air was necessary. My Towmax are happily residing on a couple 16' equipment trailers hauling concrete form lumber.
As far as scrubbing, there is always going to be more scrubbing with 3 axles than 2. You can prolong the lifetime by rotating the tires, but they are still going to wear quicker. I try not to make tight turns unless I have to, especially on pavement. I don't like the creaking sounds the trailers make while turning, anyway. I just feel more comfortable doing it with a tire that has a full steel casing and outweighs the Towmax by 50%.