Nice truck!.......great combo.
I tow 14K with 07 3500 SRW 5.9L 48re 4:10 and aftermarket EB and have always had pleasant towing .......no white knuckle/Mr. Toad's Wild Ride.
Solid steady platform.
Any vehicle can be when matched with rig that is within capabilities (real world not mfg. magical world)
Mileage towing is 10.5-11.5 hand calculated but I use backroads and drive 62 mph.
Hopefully your tow mileage will increase over time as engine breaks in.
I know with my 5.9L mileage improved after 25,000
Was that two mileage hand calculated?
What speed do you tow at?