Al,
I have an 18'x30' room with 13.5' high cathedral ceilings. The speakers are on the 18' wall. Currently they are 5' from the side walls and 4.5' from the back wall and have essentially no toe-in. I sit 8' from each speaker, which are 8' apart.
This setup works great for me, but I am always fiddeling around. As little as 1" can make a large difference in the soundstage, so it pays to be patient and move the speakers around, listen, and make measurements.
Since the speakers are very difficult to move, I purchased some large restraurant cookie sheets and cut some MDF to fit. I put the speakers on these sheets for easy repositioning during testing.