No direct experience, but you might consider switching to LT tires if you haven't yet done so. Preferably a size or two shorter sidewall, too. Shorter, stiffer sidewalls are less susceptible to squirm when the fulcrum force of the TT acts on the back of the TV.
You have a short wheelbase vehicle, 114.7" and that works against you with such a long TT. I have towed a 23'8" Rockwood, close to 4000 lb loaded, with a 111" wb Mercury Mountaineer (2000) and it felt pretty unstable until I added the 4-point Equal-i-zer to it; then it felt very solid at all times.
