What do you recommend? We have the same rack.
I like the 8 footer personally. Here's what my 8 foot ARB looked like setup on my Gamiviti rack. At the front, it extends just beyond where the A pillar descends. At the back, if you were to drop a plumb line, it would be vertically aligned with the rearmost point of the bumper. The 2 extra feet makes a HUGE difference IMO.