You should take the time to learn
how to adjust your WDH.
This WDH primer may also help your understanding.
In addition to those references, you should understand how the Reese dual cam system works. It is picky about centering the detents on the bars on the cam lobes when driving straight. Many basic WDHs are not adjusted properly from the RV dealer, let alone the picky Reese straight line.
I have the same WDH. I have experienced stable at 75mph as well as scary at 60mph with the same truck/trailer combo. You have to get the adjustment right. And my TT tows well behind a dually with no WD, so the trailer/loading itself is stable.