R&S is yellow, green, orange, blue on my RTB2004. You can apply effects (e.g. to show up infrequent events) on a channel but can't change the base colour.
Zero issues for me, but I have good colour vision. Configurable channel colours (given they're using RGB LEDs as channel indicators, it should be easy-ish) was a feature request from some on this forum but unlike others it didn't make it into new firmware AFAIK.