Both sides or channels have to overlap or you will get a “Hollow Spot” in the center. Aashideacon, you have it just about right with 9-3 with the short distance. That’s about what we used years ago depending on how far we had the speakers apart. Sometimes it wouldn’t be any further that 10-2 which was OK too. The limit was no more than about 8-4 which about was far as you dare to go. If you had multiple Columns set up down the sides of a larger auditorium, that was even better and you didn’t get a lot of “Bounce Back”. On the mixing board, it depended on each instrument and how loud or quiet it was coming across. Sometimes, I set the drums slightly off center by about 1 or 2 either left or right depending on a personal choice of the listener. On recordings, it was rare to set the drums “Dead Center”. You didn’t seem to get any depth that way. It’s hard sometimes to setup unless you had someone out there in the crowd doing the listening. The best way to get a good setup was to face away from the stage and get the bounce off the walls when you’re standing in the center of the hall or room. Sounds crazy, but using the ambient sound was sometimes the best way to set it up especially in a large auditorium with a lot of natural reverberation.