Well to start out the tank I am going to build a LED fixture for a 30g aquarium which is 36"x12"x16". I want to keep LPS, zoanthids, and clams; and eventually move up to SPS corals.

I want to use the Cree XM-L LEDs but I don't know how many I can safely put over a 30g aquarium without killing off coral.
Which drivers would work with XM-Ls as well as be dimable and affordable?
What color ratio would work best using XM-Ls and RB?
And my final question is should I use a row of LEDs in a line or make 3 LED pucks on a 4.25" x 23" heatsink.