Making the switch to LED's

[ConnorG]

I'm finally thinking of making the switch to LEDs from my metal halides! What I'm thinking is getting the retrofit 48 LEDs and splitting 24 on each side of the tank. I just don't know what colors to choose for it. I have a few questions.
- what color combo would produce best color?
- is this enough LEDs to replace my metal halides?
- what else do I need?
- what heatsink would be best? Size?
- what degree of optics?

Thanks!!