Personally if I was growing in a 3x3 area I would only grow one or two plants for a scrog grow. If you are growing 6 plants in a 3x3 area I do not think it would be the best idea. Unless I read something wrong.
Here is a really sweet scrog grow
http://boards.cannabis.com/grow-log/...ry-sativa.html
You can check out my purple diesel sog grow in my signature. That is another idea. Even with a sog I would only use one strain.
what is it that you are trying to do?
You want to grow 6 strains in a 3x3 area?