the problem you are going to face is not about how tall they can grow, it's when you add your water, the path of least resistance is down the side of the inner wall of your container so the nutrients get leached out to the sides causing your root system to become compromised, it seems like you...
I live in the Portland area and I have 3 species currently forming roots and will be available in roughly 10 days..they are Star Trek, Madicine Woman, and Kona Kola (Hawiian species). If you are interested, please contact me at my web address..
Peace! GreenerMan2112
the difference that you are trying to figure out is light penetration. While you have to keep your plants close to light source, depending on the species you are trying to grow, it would be generally more cost effective to use a 450 watt lamp rather than a 150 watt