A lot of towing pull behinds is trial and error at first while getting it dialed in. First thing I'd recommend is getting the height of the hitch adjusted at an RV or trailer dealer if you haven't already. They will set it up the way it should be for your truck. Then play with the settings on the load level bar chain links a link or two at a time. We made our cclb level front and back in the amount of room between the top of the tire and the top of the wheel wells. Which, after we loaded the bed of the truck with supplies, actually lifted it back up a bit by shifting more weight to the trailer. Changed a chain link or two for more weight on the truck depending on if the roads were wet or not. Rear Tires were at max psi when towing on stock size E rated tires.
Tow it when you're trying to set up the links and pressures the same way you'll tow every time you tow. Don't move weight around inside to try to make it better, leave it as close to the same as you can every time. 35' is a big beast for a tow behind.
Using only one bar is basically only removing weight from half the load. Both bars will even it out like it should. Play with the weight your putting on the hitch after your tire pressures are set. If the front is floating over bumps, too much weight on the back of the truck, back the bars off a chain link. But don't take so much off that your going to lose traction if you have to slam the brakes. It'll take some time but you'll find it eventually. Don't be afraid to stop to make a change to the bars either. Once you figure it all out, write it down or memorize it depending on conditions.
