Just curious if you were in tow/haul when you had the difference in opinion on which gear you thought you should be in. If not t/h how about in cruise.
I had my Rockwood toy hauler loaded down to about 8k and have been really happy with the performance of my super duty gasser. I get 11.5 in the flats with the trailer according to the computer.
Great report and I bet you had a blast.