DIY LED Questions

I've been reading a TON about LEDs and I'm to the point where I think I understand what I need but there is SOOO much information and conflicting opinions. I also noticed that a lot of the info is a few years old so want to make sure I'm using the latest and greatest LEDs and info. Figured I'd throw some questions up and get local opinions.

I'm going to set up a ten gallon SPS tank with a ten gallon sump. The questions I have are basic...

1.) How many LEDS should I go with
2.) What colors - include a cyan or no??
3.) 3w Cree XP-E the best option?
4.) Dimmable driver or not because I plan on connecting it to a controller with dimmable pattern programs
5.) Cheapest Stateside supplier
6.) Color pattern

Thanks
Bruce