ATC scm 7,11,19 best position?

No toe in. Like mine 4 to 5 feet off the walls and use acoustic treatments directly behind. We keep ours in the center of our recording stage.

I prefer the ears at woofer level with my scm20. I have them about 6 feet from the back wall and approximately 3 feet from the side wall. It creates great depth and an infinitie soundstage. Like shardone said, i also do not toe in my speakers.

I prefer no toe-in - just straight ahead provided you are 3 to 4 feet from side walls (otherwise an aggressive toe in may be needed to reduce unwanted reflections)

Since the woofer/mid runs up to around 3 KHz on the 19 I'd suggest keeping this driver at ear level and away from reflective surfaces if you can (they work best on a stand).