For sure, a dually always gives the absolute most stable
The ability to control lateral movement with 4 tires is impressive, and were I full timing - I'd rather over do it than underdo it.
Pay attention to your payloads on a vehicle by vehicle basis as there can be a wide range in payload capacity of trucks even within the same year and manufacturer.
So, I would select my fth wheel first, truck second.
Not sure your level of knowledge on the subject, but many seem to miss this point, especially if guided by a car dealer (the worst thing you could do)
But a primer just in case.
Payload is the amount of weight a truck can carry straight down on it's frame.
YOU are payload.
your dog is payload.
a load of firewood is payload.
Your 5th wheels pin or hitch weight is payload.
Towing capacity is the weight rating that the drive-train can pull. That's the gross weight that can pulled be forward.
Most every truck can pull the moon, but you can't always set the moon in it's truck bed.
I generally think that ALL 5th wheels are 1 ton territory with the exception of some smaller 5th's in the 26-28 range that still sort of stress a 3/4 ton, but is sort of doable - but not by me