I have a Jayco 165 Sport.
Dry tongue weight is 400lbs.
My trailer guy told be previously that you needed 400 lbs tongue weight to use a WDH.
My 4Runner was down in the back probably 1.5". I installed a WDH Equalizer E-2 with anti-sway built in.
I have not seen any bending of the TT frame.
Measure your front fender height hitched and unhitched. You may not be lifting much weight off the front axel.
The only way to get firm numbers are at a CAT scale.
Looking at the specs on the 154BH, 3200 GVWR, I would probably see how it felt and handled without a WDH.
Not familiar with the Swift tongue strength, but could be a concern.
You could also email Service@Jayco.com
and see if they recommend a WDH with the model TT