I'm 5' 10" tall and weigh 175 lbs. and sleeping alone in the car. The Tesmat is comfortable itself, but the slant of the back seats means that the "bed" is more like a "recliner" and I slowly slide into the trunk, meaning that my feet touch the back of the car. This wakes me so I have to slide up again, so I can't get a full night's sleep.
I had hoped that the Tesmat would compensate by making the bottom of the mattress thicker than the top, thus giving a more level sleeping surface.
To solve this, I bought a self-inflating mat that I use in the trunk, plus a hiking table that I lay near the top of the folded back seats and on top of the self-inflating mat, then I lay the Tesmat on top of that, giving me a near level bed. That seems to work fairly well (though I've only slept on that configuration for one night).
The privacy shield has a "shiny" side and a "mat" side, but no instructions regarding which should face in or out. I found that "shiny side facing in" works, but "shiny side facing out" is difficult to fix in place. Would be nice to have that suggestion in the instructions. Otherwise, I find that works well.