You may want to try experimenting, if possible.
For example, some of us have found that if you have speakers with good dispersion not absorbing the first reflection point actually adds a good amount of spaciousness.
Interesting. Yes, experimentation is in order, although I'd need to get panels to start with, and I'd also like to minimize any drywall work. I'm not thinking of doing the ceiling for now (ceiling paneling would seem hard to experiment).