I had read about the light
front end on my 21 fb which I pulled with a Silverado 1500. The only time I ever noticed a problem was when I took it dry (ie no propane
bottles and no battery) to have a battery
pan installed below and behind the propane
containers and also no water in it. After installing a dual battery
set up and putting the propane
containers and getting it ready for travel with water and other needs I never noticed a problem with swaying.
Adding 500 # weight
was in my mind not necessary. The batteries I installed added some weight
and the 32 gallon fresh water made this unnecessary. It was effected by a strong side wind which prompted me to put a sway bar and load distributing hitch. Never been a problem in my view.