Lots of opinions on over tiring your trailer! IMO...it is unwise to way over tire! Going up one load range is normally okay, but I then recommend running that tire at full sidewall pressure, to gain any advantage. If you have been running Ds at 65 psi, and keeping within the tire wt rating, I would not go to F rated, and not run max pressure. If you feel the need for more wt capacity, I'd go to an E-rated tire, and run the full 80 psi. If your wheels have Ds from the factory, the wheels are likely rated to 80 psi. The F rated tires likely rated to 95 psi may not work with your wheels at full tire pressure. Sure you could run the Fs at 80 psi, but to what advantage, and may make them run hotter.
Jerry