So I am sure you know that there is an endless debate between LT and ST tires for trailers. I have done a lot of research and have discovered that I know nothing.
But you might want to go to the Goodyear Endurance site and read their technical stuff. It was very persuasive to me, as an ignorant person. They say that trailers need special sidewalls and that the new Endurance is specifically designed for that purpose. My reasoning is that since they are the ones who will get sued if their product is not safe for the intended purpose, they have an incentive to make a tire that will do the job. I could be wrong, and often am.
My amateur advice is to get the beefiest Endurance that will fit on your trailer. I got Load Range D for a tiny 2500 pound trailer, which is like putting hiking boots on a Chihuahua.
After 20,000 miles, I am very happy with these tires. But anecdotes are not evidence, as the scientists say. ;)