1 fur sure not getting the 100 some were in middle might be pushin some strains while others be needin more to less. Why not tryin to grow what yual need and tweek it from there friend hope yual find yur trails well.
A SCROG is a grow designed to utilize a small space to reap larger harvests out of fewer plants. If you have two or more 1000w HIDs, and the space to grow them, why not grow more plants using HST, LST, or flemming to produce more buds per plant, that way. You will be able to grow more bud than with a SCROG, because the SCROG is limited to your ability to reach under the screen to train your plants. JMO
Two 1000W lights will adequately light about 50-60 sq ft. You will not be able to utilize the entire basement with 2 1000s, but will have to erect some kind of reflective enclosure or buy a tent or 2. Plant count is an individual thing. You can veg them for a long time and run fewer plants or veg a short time and run more plants. I am with Menimeth on the scrog thing. I also think it is best in small short spaces. I think that other training methods would work better for a larger space--topping, fimming, lollipopping, etc.
Were you gifted hoods also? Are you going to be able to cool these? I am guessing probably an 8" fan would probably be adequate for 50-60 sq ft.