I read a while ago on the S&B board about products for grey/brassy blonde hair and have bought some today. They are the twice-a-week brightening and daily shampoos and the conditioner. I have a mix of grey, blonde highlights and dark blonde hair ................... will these products be ok? I just don't want to end up with a purple tint to my hair but would love to bring out my natural grey. Any tips before I 'go for it' tomorrow?!! TIA