2-600 watters will give you 37.5 watts per square foot,which is a little on the low side but doable under the right conditions:

1. Scrog grow

2. Go with a narrow air cooled hood that projects a rectangle pattern instead of square.

3. Use 6 foot light movers with the lights starting out at opposite ends of the grow. By using light movers and air cooling you can put the lights as close as 6 inches to the top of the grow.