Well, I don't wear alot of makeup, but when I do I never colour my brows. And to be honest none of the women I know do. My natural eyebrows are ... hmmm ... hang on ... goes and looks in mirror ... about one and a half shades lighter than my hair. And it's boring brown btw. Blonde is such a hard colour to do, especially when you aren't working from a specific reference. Perhaps light and medium blonde as options?