I've got a similar rig, but a gasser, and my TT is 6500lb dry. I'd really recommend a WD hitch, I occasionally tow about 5 miles from the storage place to the house without it, and you can really tell a difference, and I'm going less than 40mph. It is much more stable with the Hitch connected.
i use a Blue Ox Sway Pro hitch, and I'm really happy with it, but it is my first WD hitch. My tongue weight is around 900-1000lb depending on load. I emailed Blue Ox about which spring bar, and they recommended if you were on the edge of the weight to go up a size. They said it was better to have heavier ones lightly loaded than the smaller ones torqued to their max.
2022 Ford F-350 7.3l
2002 Chevy Silverado 1500HD 6.0l 268k miles (retired)
2016 Heritage Glen 29BH
2003 Flagstaff 228D Pop Up