Many make the move up to E-rated tires, due to their D-rated being barely adequate. In your case, (light weight trailer) it would not be needed, as the D-rated are 2,540 at 65 lbs. If using E-rated at 80 lbs, you would have more capacity, but your suspension and trailer contents will take more of a beating. ST trailer tires should be run at max pressure, so IMO, it would be unwise to buy E-rated, and run less than 80 lbs pressure.
Maxxis tires have been better than most STs. However, the newer Carlisle, and the Provider tires are worth considering. They have a higher speed rating, due to a cap that is supposed to run cooler. I don't tow over 65 mph, but it is good to have a tire rated for 81 mph. My FW came with the Provider D-rated tires, and they have given me good service.
Jerry