Center of the hood(1) to center of hood (2) no more than 6 feet max. Your 600watt covers a 6 foot x 6 foot area. Imagine each light a 6'x6' box light(hood) in the center. 3 feet to the edge of the imaginary box, 3 feet to the edge if the imaginary 2nd box. Total distance 6 feet max. If you can go less you'll get better coverage.? what does that mean