Light/Plant areas for my medical grow. Help

Hello RIU. Im planning the setup of a medical grow. It is bigger and more complex than im comfortable/confident with doing without advice from more experienced growers. Ive always used the sog technique so things like spacing im unsure of. If theres anything you think could be more efficient PLEASE let me know lol.We can have 18 plants max in flower. Obviously i want to grow these as big as possible within light limits. I was thinking (correct me if im wrong) about vegging to roughly 3 ft. Finishing around 6ft? We decided to try 10x ten gallon pots and 8x 5 gallon pots. The 10 gallons are going in the center of the room where there is lots of vertical height (check picture). Being generally a 6ft plant and maybe* 8-9 ft plants in the center. I was thinking they each need to be placed about 3 feet apart. To light the room we decided to buy 12x 1000w HPS's and arranging them like so. (picture) And arranging the plants like so (picture) Points to note-no topping,indica dominant strains,no co2 Discuss- http://i56.tinypic.com/2zewm4n.png I also have some venting questions too if anyones up to it. lol