Check out the DIY forum, there are TONS of very long and very informative threads. If you need help finding specific info lemme know, I spend a fair amount of time over there. Or if you wanna see some DIY LED stuff in person lemme know and you can stop by some time.
But yeah, getting the intensity to keep clams or SPS is not a problem. These days it's just as common to have builds that are too powerful (since people often build on "rules of thumb" based on last-generation tech). The real catch with DIY rigs is nailing the color balance to keep *everything* in a typical tank looking good. Though, to be fair, people have the same struggle with other types of lighting (look at all the "which T5 combo is best" threads). It's just that with LEDs, we're still kinda figuring it out, and you have many times more variables to keep track of, since instead of 4 or 6 T5 lamps to pick, you might have 40 or 50 LEDs...