Great idea Redkiwi, I've been experimenting with this for years. I currently own Thiel 3.6's. I have tried the Cardas rule but just usually experiment to dial in because my room is a little odd. It's a partially finished basement and measures 14.5W by 45L by 8H. My front wall is approx. 6 ft wide with 2 cavities on either side approx 5ft and 3 ft wide. My son's closet is on the other side and makes this identation into the room. It would be hard to dial in a rear firing speaker. Right now I have the speakers 48" off the front wall about 8.5ft apart which leaves my around 4 and 3 ft from side walls. I sit about 9 ft in front. Thiels have a wide dispersion so I don't usually toe-in although I play around with this it seems all the time - I can never be completely satisfied. I use a wool horse banket on the wall between the speakers and 2 on the side for damping, this seems to help imaging. Other than that damping material like foam seems to deaden the sound too much. My ceiling is unfinished - wood joists above me - don't know if this is good or bad or indifferent. Maybe defraction. Let me finish with a horror story, if you're quezy at all do not read on. Just yesterday I was fooling around and accidentally knocked over a sheet of drywall that was leaning up against an unfinished frame(STUPID IDIOT!) It fell into my speaker, tipped it over(GULP) it landed on my amp, fortunately on the face plate of my Classe, knocked the amp off the stand on its side, the speaker then rolled to a stop. Put a half inch gouge in the top right on the corner of the speaker (LOOKS REAL NICE). The place looked like a crime scene, cables everywhere - man. Well everything works or I would have crawled up on the roof to jump. Ever see the movie Jaws and Quin said the scariest moment of his life was waiting his turn to be pulled from the shark infested water, well mine was booting up waiting for the tubes to come on in the preamp to see if I could still produce music!