It is hard to understand the difference in hauling between DRW and SRW unless you drive both.
I've been having duallies for years since I haul heavy equipment and stuff.
Once I was pulling heavy trailer on the freeway when my aging tire on the rear blow. Being that Friday night and 100 miles to home, I gave it try to drive on single rear on one side, but that blew few miles later as well.
In desperation - having new tires on front, I put them single on the rear where I had heavy load. and put aging tires on front.
That instantly made for white knuckles driving even I drove 45 mph.
Made the 100 miles home, but took me almost 3 hr.