Hey there, welcome to AC!
I'm not sure if there is such thing as perfect lighting, but with a 24" deep tank, I would push for two 175 watt metal, halides, supplemented with one or two actinic fluorescents (my preference is T5, but PC or VHO will do it as well). The haldes will be the main powerhouses in terms of photosynsthesis, but the actinics will bring out the fluorescent pigments. They can also be turned on before, and left on after, the halides, to give a decent dawn/dusk effect and extend your viewing time.
I guess you could try a single 250 or 400 watt halide over the middle.
Or, there are some nice 8X39 watt T5 fixtures out there that could do the trick as well.
Hmmmm. I guess there isn't a perfect setup. Depends on your goals, wallet and ability to DIY.
What were you thinking about keeping?