My experience in such a tight space is you could probably do two with 16 branches each or 4 for with 8 branches. You will have to lollipop fan leaves to ensure light hits lower level of branches. I would not let any sites form below 8 inches from the tops to ensure nice fat colas on the top. Check out this link http://www.rollitup.org/t/second-time-grower-first-time-indoor-here-we-grow.789125/#post-10432438
