Stunzeed:
I'm a new kid here, but not too new to growing.
Is this your first grows? If so, I would really suggest going soil the first time around, at least. Get used to all the details that go with raising these plants, as once you switch to hydro you need to be able to react to issues much faster in order to avoid catastrophe's. Soil is MUCH more forgiving.
In the 12x12 room, how much space is dedicated to growing benches, or are you just planning on setting them on the floor?
Another issue to consider is the electrical power available. At 240V (likely you'll need some PROFESSIONAL rewiring for that) at 1000W will draw approx. 4.5 to 5 amps, and at 120V it will draw 9.5 to 10 amps. That's a LOT of current! Your household wiring likely has 15A or (if your lucky) 20 amp breakers, so you'll be limited on how many lights you can run just by the available amperage. DO NOT draw more than safe current, or your asking for blown breakers, or worse yet, a fire. Do not change out the breakers for higher capacity (like 30 amp. ) as the wiring in the walls can not handle that level of current, and will catch fire before the breaker goes...that is mucho bad!
Start with the easy questions: If soil, I would go with a 1000 MH/HPS and if you have the available power add a 400W HPS along with the MH (nice spectrum that way). Keep in mind you have to have enough air to cool and circulate in that room, otherwise you woin't be able to manage the temps.
Personally, I would be using T-5's for vegging (if you are current limited) and the pack the power into your flowering lights. If you did that you might be able to run 2 of the 1000W HPS's for flowering, giving you max yield for the space.
The T-5's do well, especially in hydro set-ups for ebb/flo, etc., but they also have their issues as they need to be close to the plant tops. Easy to do in ebb/flo as all plants start out the same height. The flouro's don't have the heat issue to deal with, saving you amp's on intake and exhaust fans (you still need fresh air in/out of the room and another fan for circulation running 24/7)
You ask a BIG question in a few short sentences..
ISO