Almost all hitches need to be re-done after leaving the dealer. First of all most dealers techs do not have experience in actually driving a rig and set up the hitch by the written directions - if they even go that far. Secondly, they are setting it up for an empty trailer and you do not tow it that way when you go camping. You should load your trailer like you are going camping, then adjust the hitch so the proper amount of tongue weight is returned to the front axle of the tow vehicle and the trailer is level. Those are the two main goals of setting up the hitch correctly.
I would switch back to the stock tires, get a shank that will let you lower the tongue so the trailer is level when being towed, and take a good long look at
this sticky thread which will help you set your hitch up correctly.
That thread has a lot of information in it via clickable links that you should use to find your particular answers. It was written quite a long time ago but has been updated frequently so it is quite current. Hope it helps you out. :)
Barney