I need to light a monument sign. The sign is arc shaped with a slight inward curve The inside arc is 18 feet and its height is 9 feet 6 inches. The lettering is centered vertically and is about 2 feet high. I want to light it with LEDs to conserve energy and maintenance. The lights will be in an area with sprinklers. How many lights should I use and what would be the recommended wattage for them? Are there particular brands that are better than others?