Recommend Tire Pressure

Donn is correct. No one knows how much pressure need. You determine that from the max pressure on the sidewall, and the weight you carry. There may be a time where the max is too much, and that is determined by visual treadwear. If you run max pressure, and the center tread wear is not excessive, then you can't do any better.
There may come a day (maybe on a cargo trailer) when you mite need to run more than max pressure, such as in an overload situation. Running over max pressure is much better than failure from an over heated tire.