The only advice I can give is based off of my personal experience. I would put 2-4 in there, though I veg my plants for two months doing Low Stress Training with them, securing main shoots to bamboo posts and then tying back anything extra to the pot (with strings and holes drilled into the rim of the pots). This way I encourage branching while preparing a flat canopy for the screen to come over top of. 2 weeks before I flip them into flower I secure a wire screen to four bamboo shoots placed around the rim of the soil ( I use 10 gal pots, and transplant a week prior to putting in the screen so I can insert the bamboo without causing root damage. I am able to fill a 3x3 foot (9 ft. sq.) screen with a single plant. I find that putting the screen on right before flower, rather then training the plant into it gives you a much more squat and controlable conopy. Granted this is hard to do if you want to put all of your plants into one screen. I personally do not do this because I like to still be able to access the plants individually and move them around the room as they grow and change. Also it is very important to maintain the underside of the canopy and cut away anything that is not recieveing light throughout the flowering stage. If you want to fix your screen to your space, remember that you are going to find yourself on the floor around week 3 of flower cutting away tons of leaf matter. Because my plants screens are just for them and connected to their pots I am able to make them out and put them up on a table where I can better see what I'm doing without breaking my back.
Anyhow I hope my ramble helps, SCROG on!
oh and get on youtube tonight and search The Best SCROG Video Ever, by budbook. This guy is the master of SCROG. he gets more than a pound per plant! granted his op is large scale but there are plenty of awesome lessons to take away from seeing his grow.