Feel free to correct me, but i think you are missing the point DJ. The Potentiometer allows you to "mix" your colors to get a specific shade by having variable resistance. the Resistor sets it at a fixed color that you cannot change because of fixed resistance. These do two very different things.

CC brings up a good point. If you only want that color and don't want to worry about adjusting it, you could make the color permanent by using a resistor in place of the pot once you find the value...but the using a pot that requires a flat-head screwdriver or some such would be fairly permanent without having to re-wire the thing... Just seems like too much work to me...