When I was setting-up my previous WD hitch, I was missing a part from the kit, so I called Reese. In the phone call with the tech, he mentioned that it sounded like I had the correct weight bars, but that (like most people) I wasn't putting enough torque on them. He had me increase the tilt of the bar a bit, and use the power-jack to actually lift a bit to connect the dual-cam sway chains. This greatly increased torque, further reduced sway, and kept the truck level.
The Timbrens helped KEEP it level, once I put the kayaks on the roof, and loaded the back of the truck with all of the "extra" stuff that we all seem to carry.