A long talk with Aaron at Hensley Mfg. says to "check your set up, particularly the strut bars." He said the spring bars are NOT the problem, that it is all in the strut. I cannot absolutely rule out that the struts were not tight, as I had just dropped the hitch to do the annual "lubing of the ball" (that just sounds kinda dirty, huh?).
Adding to my frustration, and not disclosed in the original post is the fact that one of the trailer frame brackets had actually broken as we pulled into the campground in Shreveport. Thus, I took the Hensley hitch off and bought a 2nd-hand WDH from a campground resident. Because I had removed the Hensley and installed the Husky to limp home, I cannot unequivocally state that Aaron's recommendation to tighten the struts just might have solved the problem.
I had chalked up the problems to having too much weight transferred to the front axle, which resulted in excess sway (and the broken frame bracket). Aaron absolutely assured me that was not the problem and that the F150 should be able to handle the load if set up correctly. He also said that metal fatigue (and hitch age), combined with the horrible Louisiana interstates, as well as a weaker steel used in earlier frame brackets, was the reason for the broken bracket. He also encouraged me to not give up on the truck but to continue tweaking the setup and to try it again.
:?
If none of the above makes sense, it's because of the complexity of the Hensley set up. There are strut bars that are designed to "lock out" sway, and weight distribution bars that are designed to transfer weight (just as in a normal WDH hitch). What actually broke on my hitch was the pin on which the spring bar jack mounts to the frame bracket. See below:
