Not knowing much about the 1500 , and air pressure , but I’d run whatever is on the door jam for the front that covers the weight , that doesn’t change . An E rated tire certainly doesn’t need to run its max air pressure, that’s to cover whatever the tire is rated for in lbs . My Coopers are rated for 3640 @ 80 psi. As far as the rears , again the door jam is max air pressure for max payload , doesn’t have to have that much running empty , as said I run nearly half the air pressure needed for max load when running empty, but my 3500 is a lot rougher riding than a 1500 , plus 80 psi wears the center out running empty , there’s just no where near 3640 lbs on each of those rear tires.