From your post simply moving to the larger and longer TT is putting your truck at or beyond it's limits, most 1/2 ton (150/1500) trucks are out of payload well before they reach their overstated tow capacity. Secondly, the sheer length of your new rig will make towing at highway speeds a white knuckle experience and if it is windy as well it will certainly test your will. It's possible that an Equalizer or Dual Cam WD/SC hitch would prove helpful in dealing with your sway issues but it may take a high-end hitch like a Hensley or Propride to provide the comfort level you expect while towing down the road. Good luck and hope you have many wonderful adventures in your new TT.