The problem with friction bars in general is that they don't know which way the bar is supposed to be held, so if it gets extended, it'll try to hold it that way just as much as keeping it in a straight line when it's tracking properly.
For that reason, friction sway controls must be loosened under reduced traction situations which is, of course, when you need them most.
I would suggest a weight-equalizing, sway control hitch setup, especially with the tongue
weight of a Casita 17.