You are actually better off with a light that fits the dimensions of the tank. The 36" 2x96w would be a better choice than the 24" 2x65w that you may have been considering. The 4x96w that Atari
mentioned would even allow for more diversity in your coral selection such as SPS
and lower light clams. The only problem there is you may need to retrofit due to standard hoods for 4x96 being 48". The problem with PC
lights (and most for that matter) is wherever the light leaves off there will be shaded areas making most of what you will be able to place in the tank relegated to nearer the center of the tank, especially if that is the only place where the bulbs overlap. With the bulbs (not just the hood) being nearer to the same length as the tank, you'll have less issues with coral placement.
Whichever you choose, just be sure there is sufficient light penetration in all areas of the tank. The lowest I would choose being a 4x65w though.