you didn't say how tall your grow area is? I would just add 1 CFL a side per 8-12 inches. The idea is to get as much light to the budsites as possible. rotate them once a day or so to help that. I doodled a little room in MSPaint :rasta: hope it helps some. :] just remember that plants stretch when they're initiated into the flowering cycle. And only add CFLs if you think that the 250w HPS isn't enough. I use a 400w HPS and that's all for my flowering room, but my veg uses multiple CFLs.