The ideal fit to set up the Rev Tent for sleep in the tub of a Ute is (w tailgate down). But the Rev Tent will fit is narrower tubs. The mattress of of the tent is 1193mm and can be compressed slightly. There is also a bit of flexibility in the tent poles. We have seen the tent set up and working perfectly fine between the arches of a Ford Ranger (1139mm width), and Nissan Navara (1134mm width) and LDV T60.
For other utes with narrow distances between the arches, like a Hilux, Triton, or D-Max, you'd have to compress the mattress more. The Rev Tent will work, just note that the mattress may not "pop" back in to shape after use.