Tire Ratings / Weight / Math

Those 20" P tires are probably max rated at 44 or 51 psi. Never over pressure a tire but I would use max sidewall pressures especially in the rear tires as its carrying all the load.

I pull a 10k bumper pull car hauler with a 1500 crew cab 4wd chevy riding on P265/70-17 " tires. The bigger load is a 7400 lb blue tractor with a cab which adds 1000-1100 lbs on the trucks rear axle depending where the tractor is placed.
When towing or carrying loads I pump the trucks rear tires to 44 psi max sidewall pressure and 35-38 psi in the front. The trucks front axle doesn't change weight so I have no need to use different pressures.

Having owned several 1/2 ton trucks since the late '50s, I've tried using LT D and E but always went back to a P tire...or a C load range if I can find them.

Yup, air em up until you like how it feels. Even though a little trailer should ride just fine at 40psi on those tires, especially with a wdh.
You could toss the wdh though, not needed in the least for a trailer that size

Isn’t your tire’s max weight rating at max pressure?

Thanks, first trip is approaching so I am just looking for things to worry about. The absence of LT is what had me second guessing.
The sidewalls flex a bit loaded, (naturally) but not excessively. I've been at 40lbs and they max at 50 so I imagine I should go up a bit?

Hitch looks like it's this exact one. https://www.etrailer.com/Weight-Distribution-Hitch/Fastway/FA94-00-1033.html?feed=npn&gclid=EAIaIQobChMI5Yv2ksnG6wIVrNSzCh2_4Qx4EAQYAyABEgIaNfD_BwE

Thanks again!

Tires are 2679# EACH so 5358# total per axle

4400# GVWR trailer is NOT going to overload your truck

What do you have for 'hitch'???