Above is an excellent document for tire information.
For Goodyear, use their tire pressure weight ratings chart as you are doing.
Good Year Tire chart for 245/70R19.5 and tires made after 2/26/08, cold 80 psi is good for weights up to 3640 lbs single and 3415 duals. 80 psi is too close to the max ratings for your weight. It doesn't allow or permit enough variance.
I would go at least 90 psi unless you plan on weighing your vehicle every day. You need some room especially in the duals. 90 psi would give you: 3655 lbs for the duals. You are running 3310, so that's not much of a variance.
Actually, without exceeding your rim pressure limits, look on the tire sidewall for the max psi at xyz... Yours is 95... That's the maximum your tire can perform within design specs. Anything else is overload and dangerous.
TiP: Maintain duals psi to match as close as you can and within 10 psi... Anything else can cause overheating, and you are dragging the lower psi tire.
"Tests conducted by Bridgestone/Firestone found that a five-psi difference created a 5/16-inch difference in tire circumference on a set of dual tires. In only one mile, this slight difference caused the smaller tire to be dragged 13 feet.
A truck that drives 100,000 miles per year would drag this tire 246 miles. "
Cold Tire psi will change as you cross-country with different climates and elevations...
Your 85 is OK