I'm building a micro grow in a box that is 16.5" x 15.5" x 17.5" and plan on using a hydro system and the scrog method. After Installing the lights and hydro system there will prob be around 8" between the water reservoir and the lights bulbs. How much do you think a box this size could yield? I am hoping to get 18-28g out of this box. Does that sound reasonable?