After some thought, I have decided to put my 1000W HPS in the original flowering room which is 19.5 sq ft. I will put one of the 600W that is now in my flowering room in the new closet (2 x 6). I ordered a fan and speed controller the other day. I got 25' of insulated ducting free from my someone and have decided to do 2 ducting runs between the 2 rooms. As soon as the ventilation for the second room is up and going, I will put one of the 600W HPS in there. The 4 BTB that are in there now (under the 300W and some jury-rigged ventilation) are growing well, but still not showing sex.