I did haul my own chair at times to avoid the woman's horrible couch.With her couch, I sat exactly in the middle to avoid her equally horrible pillows.She had a whole gob of pillows.
In the room set up you have - if someone was holding a gun to me and made me sit on the couch, I would choose the end of the couch closest to the door/farthest from the therapist.
But I would probably just take in my own chair to avoid getting trapped in there by a therapist