need tire pressure advice
TV: 2014 GMC Sierra CC 5.2 with tow package. I had been thinking about replacing the factory Bridgestone tires, 245/70-17, on my TV as I have just a little bit of sway pulling my TT. The TT is a 2015 Coachmen Freedom Express 310BHDS. Someone ran into the drivers side of my truck back in February and that left me with two left side tires with flat spots, he pushed me 45 feet after hitting me. The ride with the flat spots led me to put the new tires on sooner than I had planned. Hopefully my lawyer is going to get some monies from the other parties insurance to offset the price of the new tires. I have had Toyo tires on two previous trucks and really liked them. I had new Toyo tires put on this morning and the tire dealer stated that they had no idea of how much air pressure to put in these tires as their charts did not show an application for my truck. The tires are Toyo Open Country H/T LT265/70-17 tires, an "E" rated sidewall. The dealer put 60# of air in them just to get started and I have to figure out how much to run in them with and without the TT hooked up. I took the long way home over some good roads with the 60# and the truck rode really well, a little bit rougher than the Bridgestone's but I expected that. So, does anyone have a recommendation as to how much air pressure to run in these tires with and without the TT hooked up?