JVCs that had LEDs back in the day, such as the PC11, 656 and that tiny one I have around somewhere seemed to come with red LEDs rather than the red to yellow arrangement found on some makers' stuff so you could stick to red for that reason, or, seeing as it's your toy and your way, you could have seven on each channel; one of each colour. The potential disadvantage of using the entire visible spectrum is that it would look like it was related to a Discolite.