I'm colouring my mother in laws hair today, now she reckons her salon uses wella highlift on her hair but shes got a base which is almost 100% grey on top, would a highlft cover this, as i wouldn't of thought i'd use 12% on that much white, however I would on the back as she's quite dark around the nape area, her colour is quite brassy around this root area too, but her overall look is a very light ash blonde.