I did mention of going from DRW to SRW in my chain of trucks.
At the time I was using truck for 18k lb trailer pulling and thanks to going from 4.5 differential ratio in F450 to 3.5 (?) in F250 with SRW I saved over 25% on mpg difference, even both truck had the same 7.3l engine and F250 was 4WD to top it.
But when I went long way to pick up my 12' TC, I stopped on the first scales I found on my way back.
Even I bought new tires with the biggest weight ratio on the market and put spare wheel on front bumper, winterized camper overload rear tires by like 300 lb each.
So next day after getting home, I start searching for dually.