#Tiny LEd controller
tribal reef
cinder haven
For efficiency in terms of light output to power draw, you'll have to calculate it yourself from the datasheets. As far as controlling the LEDs are concerned, digitally controlled LEDs aren't necessarily the most energy efficient. I would lean towards using something like a current-steering DAC (or digital pot + adjustable LDO regulator). Theoretically, a current limiting config will save more power if you aren't running full brightness.
In practice, the analog approach is probably both more complicated and more expensive than you want.