I am in the process of evaluating shelter options for backpacking with my family of 5. One possible option I have come up with that looks somewhat appealing to me is purchasing a Hilleberg Nallo 4 GT. The GT has a huge vestibule. What I am thinking is that I would put my wife and kids in the tent, and I would sleep in the vestibule in a bivy. We would get the best of both worlds, my wife and kids wouldn't have to deal with a floorless shelter and I would get to sleep under a tarp. The floorplan of the tent is here:

My question for you tarp campers is this: is 83" (the width of the vestibule) going to be long enough for me in a bivy? I am relatively short (5'7"), but I am concerned that I might be too close to the sides of the shelter. Any thoughts?

