If you want trailer ST type tires; ONLY buy Goodyear Marathons Radials. You DO NOT want Carlise tires. They are crap. Cooper has a trailer tire out now, but I don't know of anyone with experiences to share. You want to buy E-rated tires for that load. You can't have too much tire.
I have LT tires on my trailer from the factory. A few folks run LT (light truck) tires on there trailer. I would say that I have had mediorcre experiences with them. I have gone through just about all of them in the couple years that I have owned the boat. They had a lot of miles on them when I bought the trailer/boat. I guess when its time for the tire to go, it goes no matter what the make/rating.
Best thing you can do for your tires is invest in a Laser Pyrometer temp guage to keep an eye on everything while towing. Each time you pull over inspect each tire inside and outside (sidewall) and each hub, brake, and sample a couple lugnuts. You can't beat this knowledge when towing. There is no set temperature they should be at, but they all need to be uniform. Tires on one side of the boat will be hotter if they are exposed to sun, as opposed to shade during tow.