1995 Ford Tow GuideThis may help.
If it bothers you that you are touching or resting on the overload springs you might consider a set of air bags. Before my air bags I was a 1/4" off the overload springs and would get a 2nd bounce now and then when I hit a bump. A set to Firestone Ride-rites gave me some extra clearance and helped my ride.
Looks like you are ok on truck payload but over on your gross vehicle. 20,000# GVWR and you are probably around 22,000# based on what you posted.
If it helps, my trailer (in signature) is 12,000# actual (14,000 GWVR) and pin about 2,600# (22%) my F350 (with us and 39 gal fuel) is about 8,400#