Looking to upgrade to a fifth wheel.

My truck is 2004.5 2WD dually with 8ft. bed and 3.73 rear end. My truck weighs 8,000 pounds with my wife and I plus a heavy hitch and a tri-fold bed cover. My gross combined is 21k#. I tow a 10k# to 10.5k# fifth wheel and the truck does very nicely. The engine could use some more grunt but for the most part is sufficient. The chassis does very well with no movement from the trailer. I could see going another ton on the trailer with no problems. I do have to monitor the transmission and switch between tow-haul and OD while towing. I added a PacBrake and would not tow six tons without it. Our engine runs hot and I monitor my exhaust gas temperatures. I find the engine will continue to pull when the EGTs are in the uncomfortable zone. I'm in a campground now, averaged 11.9 MPG on the way here, 65 MPH. Show some moderation with you trailer selection and you will like your truck's performance. I consider my pin weight to be on the light end and I am at 20%.