Thanks so much for the replies! Sorry I'm a little late with mine
hoxierice - thanks for the tip on acid dyes! Like I said, I don't have much experience in this area and so had never heard of them, though they sound interesting. It looks like there's only that one brand, though. Do you know if they're available in any chain stores?
AndreaLynn - spray sounds like an interesting alternative! I'd never thought of it before. If I could find the right color,t hat might be the best bet yet! Or maybe a combination of things done in layers.