Need help with plans for a LED room lighting system

Hey guys and gals,
I'm looking to install a full scale LED lighting system in my room, because I'm tired of blowing bulbs and incandescents, and I want something new. Id like to install a standard white light LED system for the main lights, and incorporate a RGB setup into the fixture. I want the fixture to run around the upper perimeter of the room, and contain enough lights to light a 15' x 12' x 8' room.

My questions as of now:
What are the highest output white LEDs I can get with a "wider" viewing angle?
And how can I incorporate a dimmer into the standard white setup?

I was to use this Instructable as a guide also for the RGB setup.

https://www.instructables.com/id/RGB-Color-Controllable-High-Power-LED-Room-%2b-Spot-/

Thank you very much in advance.