swaying

Nothing wrong with the friction sway control, it's the most common setup on the road, though there are better choices. You should not be experiencing sway so it sounds like something is out of whack. I would first try putting more weight up front. You said you "distribute the weight evenly" and this is not always a good idea. The trailer should be nose-heavy. Too much weight to the rear can induce sway.

BTW, you can also try adding a second way control. A lot of folks run two on a rig that long. Also, make sure your WD hitch is adjusted properly too.