That is an excellent question. I guess...maybe a medium length, slightly wavy one that you can cut. But his front pieces are straight and just curled very, erm, specifically. HM. Perhaps you can find a short, wavy one, and get straight extensions that you can style to look like his for the front?
Gah, I don't know. In Albatross, his hair just looks curly. But he's also not wearing the helmet which usually covers most of it, so it doesn't look quite as wild in strips like Shaft where he is.