What configuration of led floodlights can anyone recommend for a 140 Gal tank? I am looking for medium light, dimensions are 5 feet length by 18 inches width and 22 inches height. There's a bar in the middle so it'll make more sense to work with an even number of fixtures. 2x50W? 4x30W? 2x70W? Also, those things look heavy, where can i get secure mounting hardware?