Hi Guys
Interesting discussion. And I though some of the highways up here were bad.
Basic rule of thumb for trailer balance is 10% of the gross weight on the hitch and the rst on the axle. We ran into the same issue on the way to Florida. Had too much weight in the front. Re-located some of the weight further back overnight and solved the problem.
Other things to look at are weight distributing hitches, and anti-sway bars.
Matt, a fifth wheel is a different configuration. It's a lot harder for the "tail to wag the dog" because there is no moment arm between the hitch and the rear axle because the hitch is directly above the rear axle.
Sincerely,
Ed