Looks like you are at just about the right trailer limits for your truck!
Anything more, and it seems like it will go over one weight rating or another. I know a guy who bought a 1983 F-150 and towed a 24' Winderness fifth wheel with it. It was way before I knew anything about GVWR, or hitch weight, and I am sure it went way over both! He later traded it in on a dually 1986 F-350 with 460" engine. (the current 6.9L diesel was pretty guttless in 1986, so the 460" was the towing king with 225 rated HP!).
It seems like if you tighten up the WD bars one more notch, then you can transfer some more weight to the trailer tires and front axle, thus getting some more weight off the rear axle, and allowing you to carry more fresh water.
Fred.
