I vote for 1 plant, non auto flower. Top it when you have 2-3 nodes, let those branches grow 2-3 inches then tie them down, and top them again.. repeat that process until your have the screen filled. Then switch the lights to 12/12.
Another option would be to line the walls with a metal screen as well. This will allow you to 'scrog' the plant vertically as well as horizontally. Since your using cfl's you shouldn't have an issue letting those lights get real close to the buds. If you choose to add the vertical screen into the mix, make sure you don't get carried away with the veg time. Leave some space for the plant to stretch during flower.