The depth of the tank is what's gonna make lighting it tough, 24" is a pretty deep tank.

I've never used T-5s, but we're still talking about flourescent light. The watts per gallon rule doesn't apply well at all here. I would say that your configuration would work fine for placing corals from about the midway mark up and maybe a little deeper. Getting good light to the bottom of the tank would require more intensity.

So many species, so little money!