I have a SwivelWheel 58DW (dual wheel).
I have towed it about 6000 miles.
I have not had any issues with any vibration or wobble.
I have had issues with bounce when they are towed empty. It happens above 60mph if you hit particularly rough road. Otherwise it is not an issue.
Never an issue when towed with a load on it (which is 99 percent of the time).
2013 F350 6.7 DRW SC Lariat
2011 Brookstone 354TS
Swivelwheel 58DW w/1993 GL1500SE