Trial and error. Tech-Line still says they have a color book, but I do not know how up to date it is. If you want to make vibrant neon colors like some of the balls today, you will need the neon color pigment kit as well. I try to get the shades of color close enough that they are not noticeable going down the lane. It's pretty much impossible to color match today do to the multi color coverstocks, and pearls. One tip I can give you is to mix your pearl in after the plug has sit for a hour or so. The pearl likes to separate from the color your trying to pearlize and it just ends up being more of a solid color than a pearl.
