Get your air flow right and you can bring your light as close as 12-14" above your flowering plants. According to many growers, the close the light to the plant, the better! But you must check them daily to ensure there hasn't been a growth spurt and the fresh tops aren't getting stressed by heat. I keep 600W HPS around 24-36" away from freshly potted clones for around 1 week or until they look like they are striving in their new home. I then lower the lighting by 12" and keep the lights around 18-24" from the tops from then on until harvest. If I had Cool Shades I'd keep them closer. Adjusta-wings are good because the heat dissipation keeps the area between the plant tops and bulb relatively cool in comparrison to other cheap shade that I also use when I miscalculate space and cutting survival rate.