Is there a way to save color shades that I have created with sliders in the color panels?

I know this is a fairly detailed function I am inquiring after, but I was wondering if there was a way to create a specific shade in the RBG sliders and save it so I can use it again. I am writing a violin method book that uses colors to indicate fingerings of notes (different note-heads are different colors). But not all of the colors available with with the apple colors list, colored pencils or other sets, work. Any yellow available, for example, is too bright to be able to read as notes, the pink is too pink, etc. There are so many possibilities for choosing colors in the color panels. I can find a perfect hue by choosing an apple color and messing with the sliders but then I have do this every single time I want to change the color of a note. Is there any way to set a hue and save it somewhere in the color panels? Seems like with so many options there might be...
Thank you for helping!