When we lost our 2004 Travelstar, I kept the WDH system for my next HTT.
We now have a 2011 Palomino Stampede S238 and the dry hitch weight is 411 lbs. My WDH is good for 600 lbs.
Are we in the limits or should we look for another WDH ?
At a GVWR of 6552# and assuming 12% to the hitch that would be 786# at the hitch, more if you are like many RVers who run overloaded.
Any rating will have some safety factor, but that is not what the margin of safety is for. Besides you would not know how much margin there is. It would be prudent to get a WDH rated for the heaviest load the hitch is likely to and then some.
If you are over it could result in bent spring bars our worse. Likely that would happen when you are in the middle of nowhere, and you would kick yourself for nor getting the right one.