Ford Dually rear end preference

[Slideplayer]

Hit the scales with my current truck and camper and I’m right on the max of the truck GVWR and payload (11500 and 3450 respectively). Im looking to make the move from a SRW F350 to a DRW F350. Im considering a dually Lariat with a 3.55 rear axle, same as my current SRW. I have no problem pulling our Monty with our current setup 2016 F350 SRW 6.7 w/3.55 rear end, it s just the weight that makes me nervous. We travel interstate a lot in our journeys and i typically run the speed limit and 5 over. 65-70 mostly. One truck that i looked at had the 4.10 rear which I’m sure will get up and going quickly! The newer truck also has more torque and hp than my current truck and has a 10 speed auto tranny vs my 6 speed.
Are any of you Super Duty guys out there running the 4.10 gears with that 10 speed and how does it perform on the highway? Any noticeable sacrifice in fuel mileage with this rear end and in what gear and RPM are you cruising at say at 70 mph?
Lastly, I would hope going from a short bed SRW to a long bed DRW that the ride and stability will be much improved, right? Just a pain to park in tight campgrounds!