HI... We have a Kar-Tote tow dolly. We previously used it with our 24' Minnie Winnie, and didn't notice any problems. We purchased a 32' Fleetwood, and had to get a new hitch, with a longer drop, an...
Trailer axles have built-in camber to compensate for flex when loaded. If the ball is too low, this built-in positive camber become toe-out, which causes instability.
If you raise the ball up, I'm pretty sure your sway will go away.