I've never tried it but I've heard great things about using henna to color hair red. One tip: You should mix it with a little olive oil b/c it is very drying.

Well I imagine by now your play must be finished, what did you do in the end? Well anyways just for the record and if anyone else is interested, henna will dye your hair a beautiful flaming or coppery (depending on the henna you use and your original colour) red but it is permanent. Now there are lots of temp dyes on the market I think l'oreal has one that's a mousse or something like that Wella used to have one too that was quite lovely but they stopped making it.... aaaaaawwwwww. Former sis-in-law had a colouring mousse that only lasted till the next time she washed her hair, don't know if it worked or not it was the same colour as her real hair anyways and I didn't try it wasn't my colour. Hope your play was a success.