You have almost my exact layout, sizewise and heightwise, but I don't have the advantage of cool ambient temps as your basement space affords. I use 2 stationary 600's in air-cooled hoods over 15, 3 gal. pots. I think your idea of getting 6 elbows from a space of this size sounds wildly enthusiastic but not even close to reality, at least for now. I'm not saying it couldn't be done, just not likely. I have pulled around 2.5-2.75 lbs from my space using a high-yield variety. This yield was close to the "1 gm per watt" holy grail standard, but you are thinking 2.25 gms per watt. That would be similar to multiplying the loaves and fishes and turning water into wine.
You will need a few grows to dial in your variables and determine a good baseline yield from which to build on. Conrol the light, temps, RH, nutrition, ventilation, etc, and you will do well.
Monocropping in a space this size is the only way to bigger yields. You may want variety but it just doen't work well in a small room.
Good luck and ask questions. There are some very talented peeps here who know whats up and will help if you ask.