When u prune for vert you grow a sideways canopy prunin out the back of plants and with stacked bulbs you need tall plants or shelves of plants as you are growin sideways the upper bulb is lighting up the walls above plants both bulbs should be down low between plants for maximum lumens lighting up all the lower branches .the way its pruned now would be for a horizontal garden,youd be better off with a single horizontal bulb.plants look great though..Buddler