Rather than trying to sort through all the comments on this thread, look at what BurbMan wrote:
"Every manufacturer specifies max loads for their tires at varying pressures:
Bridgestone
Goodyear
Michelin"
Weigh your vehicle when it is loaded as you normally travel and set the pressure (cold) to what the manufacturer of your tire recommends for that tire and that load. For each axle, inflate the tires according to the most heavily loaded tire on that axle.
The pressure on the tire sidewall is not the recommended pressure. It is the do-not-exceed pressure.
If your tires are continually run at higher pressures than needed for the load you are carrying, the tires will wear out prematurely. If the middle of the tread wears out before the edge of the tread, the tire pressure is probably too high.