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Sway control is not intended to solve the sidewind gust load problem but will help it. Sway control is intended to add a yaw damping moment to the combination to counteract the natural tendency of the truck and trailer to have out of phase yawing conditions. This situation has a very significant speed causation factor, it gets (worse*squared) as you go faster. This can be a problem when the tongue load fraction is under 5%, or the vehicle speed increases (as in going down a long hill) in an unintended manner. You will reach a 'critical speed' making the combination unstable as in jack-knife. Trailer rollover is the principle mode of failure for travel trailers. Yaw damping also results from the use of multiple trailer axles. This allows you to have a lighter tongue load to trailer weight for the same combination load. The cam or friction dampers try to do the same thing. The cam lobe system enforces a predefined tongue position, The friction device adds yaw damping moments to the tow angle dynamics. There is a difference, though. The friction damper looses effectiveness once it starts to slide: the damping force is a constant at all times during the 'event'. If the tow angular velocity keeps increasing it can not stop it. The cam system adds a stabilizing moment that is proportional to the yaw angle instead of a constant value, hence is more likely to help you if you really get bent out of shape (as in a sudden double lane change).

In either case, the equalizing hitch should be alway set to maintain a level tow vehicle frame position. This keeps the front axle steer geometry and the rear axle steer geometry at manufacturer recommended positions. Now, just in case you think the rear axle doesn't steer on a front steered car, you are very wrong. There is considerable deflection steer (sideforce based), steer from roll (geometry) and steer from braking/traction (deflection and geometry) in all vehicles no matter who makes them. While its only a degree or so, tires, especially heavily loaded ones, punch out thousands of poinds of sideforce per degree, so it has a major effect on your trucks heading angle. The trailer just adds some more load to the equation(s). Keep in mind that the hitch without EQ loads the rear tires as well as unloading the fronts. This is also a geometry and a tire sideforce loading concern.

Remember the old discussion about greasing trailer balls? Well a dry ball also serves as an effective friction damper and will help you if you have nominal wind or driver induced course corrections. As I recall, those 'ex-Spurts' swore that you need to grease them. But they've probably never run engineering tests on these systems as I have, so, I stand by my statement: if you want your balls greasey, grease your ball.

AND, the place we do all this rocket science is here: (Google Earth it)

42.36'.48.59"N
83.40'.49.70"W