Congratulations on your new rig. We have the same model. Only two air units though.
We are currently in the Texas panhandle with daily temps ranging from high 90s to 105. Both airs running smoothly and keeping us at a steady 70 inside. Wasn't sure about the ducted air but seems to work well.
If we had gone with the estate with the black paint I think we would have needed the third air. Beautiful paint but I have to wonder if the designers spent any amount of time in a dark coach in full sun all day for weeks at a time.
Enjoy your rig. We love ours.
2016 F350 6.7 Drw 4.30 gears
2016 Cardinal 3825 FL
2011 Big Country 3500RL...Sold
DW, 2 Spoiled Beagles IZZY and Pup Pup,
And Hillbilly Bob an American Bobtail Rescue Cat.
Seeing America one jobsite at a time..