Yes, SOG single cola's may be 2-3 ft. What strains are good for this? The only thing I am worried about is space as you said. The first tray only has 30 but we are planning on 50-70 per 3'x6' tray,started in 3"x3"x3" rockwooland then into 6"x6"x6" square pots with hydroton. The trays are set up...