^^^ Follow Wallaby's advice. ^^^ Drive slow & safe to the scale. When you weigh the trailer and truck, you want both to be loaded up as you would for camping. With accurate weights, then you can make informed decisions.
That trailer is 10,250 lbs GVWR and 36' long! Wow, waay too much for that truck IMO. I would not go by the UVW to estimate actual wt. 500 lbs of additional loaded wt. could be way off. You will probably be more like 1,000-1,500 lbs of added wt. for 36' of trailer. Any factory options and mods. need to be factored in.
Based on the GVWR, the actual tongue weight could be in the 1200-1500 lb range. Based on the dry tongue wt., the actual would be in the 50-100 percent range higher, 1200-1500 lbs. The truck has a sticker payload capacity of 1400 lbs but could be less after going to a scale. Besides the tongue wt., you need to add the wt. of passengers, groceries, camping gear, etc. to the truck that *could* be say 400-500 lbs or more. It appears that you will be over on the GCWR and way over the truck's payload capacity. No amount of fiddling with the WDH or anything else will overcome that. You may very well be over the receiver and WDH ratings. I'm not sure you should even be towing it at all at this point.
Sorry, but it certainly does look like the next step is a 3/4 ton truck with more payload & towing capacity. I would suggest a truck with a long wheelbase too (extended or crew cab plus long box). We upgraded from an F150 to F250 and it's hard to put into words how much better the F250 is for towing.