I have a 2m x 2m area in the basement I use. I wish I had a little more space but it works well most of the time. The low ceiling is the problem - your brain is so convinced that there is sky or a high ceiling above you that you try to throw something over your head and smash the controller into the ceiling. I have marks on the walls and drywall dust embedded in my controllers. The chaperone boundaries can't do anything to warn you about that and those mistakes happen too quickly anyway.