Our screens are here but they are much smaller:
http://www.santa-monica.cc/Green-Gra...reen_p_82.html

As for your light, I think you'll find later that the top of the screen will grow but the middle won't, and the bottom might just stay white. Illumination intensity drops off rapidly every inch away from the source. But since it's already set up, go ahead and see how the growth patterns progress.