There is no exact answer to your question, but here are some thoughts.
If you want to keep sps, many aquarists (myself included) would use a 175 -10,000K metal halide. Normally these have @ a 2' spread, so that extra 3" on either side will not be a big deal. Yes, this will add heat to the tank so you must use some sort of fans (maybe computer) to cool the area above the tank if you put the lights in a canope. You can use a pendant type fixture if you would like.
Your tank is not very tall, so you don't have to rule out other types of lighting such as power compacts or vho fluorescents. If you use these types you will still have to use fans if you use a canope.
Lights are not cheap, so you would be well served reading up on the subject before you buy.
J.