Virtually all the ST tire mfg specify that the tires should be run at max sidewall pressure regardless of load. Has to do with tire design and the very high side loads on trailer tires when you turn.
Done that for many miles and tread wear has been even. I get 25K-30K miles/set and the wear is even at max pressure. Neighbor has 200K+ miles on his cargo hauler, does the same, same thing for wear.
As to worrying about heat buildup, it is a non issue if the tire isn't overloaded. Tires are designed for a max cold inflation pressure knowing that pressure will rise as they heat up or you go to higher daytime temps.
