Start with the Target Color
RGB mixes red, green and blue channels. RGBW adds an independent white channel. The value of more channels depends on target colors, white light requirements and optics, rather than channel count alone.
Check Each Channel's Parameters
Voltage, current and output may differ by channel. Check each against the datasheet when designing drivers; do not treat the entire device as a single load.
Assess Mixing in the Actual Optics
Lenses, diffusers and mixing distance affect beam quality and color fringes. Observe at the intended dimming levels and projection distance, with the actual thermal conditions.