The real bind here is what YOU want to do.
I would make the decision based on hard numbers, hence the advice to load up and weight everything.
However, if you have not bought the trailer yet, the next best is load up the truck with the family and all the toys you intend to haul and weight it. At least you will know the how much tongue weight you can add. Do not forget the WD hitch weight.
Once you know the true figures, then you can decide on how much of an overload, if any, you want to haul. I am not sure how much back transfer I would allow for the WD hitch. But in my experience, I always have more “stuff” than anticipated anyway.
It is easy to for people to say “buy more truck” but you have to live with the beast the rest of the year. My F-150 is certainly at its Max Cargo limit when I tow but my towing mileage is about 25% to 30% of my total annual mileage.
Our combination tows nice and I like the 18 to 20 mpg I get when not pulling the TT.