Very nice write up and photos with references to past and present scenarios. However, this idea of "the right gear" is still very subjective, in my opinion. Personally, I would hate to drive 70mph with rpms near 4000. But your Jeep your choice! Enjoy the ride.
Will someone tell @akajibio that the reason we push deep gears for the 42 is precisely to avoid running the trans in 3rd where the rpms would be near 4k rpm at 70mph.