I think that this has been the smartest thing said thusfar.
Now, obviously you know the intended use better than I do, but is there any conceivable (or even inconceivable) place where this logo is used in grayscale? Do all the appropriate shades work in grayscale or are they too dark/light to show the difference between the letters?
Will this be on a business card? Do you plan on having the cards done 4-color process, or are you willing to spend to have each of their Pantone equivalents printed?
Nail down the design, the form, in black on white first...then add color. Only add as many colors as it takes; if something can be excluded without affecting the quality of the design, it wasn't needed in the first place.