i would do test first , then if hair is ok , i would do a cleanse do midlengths and ends first as this is where the buildup is, when you feel its about half way to the depth you require rinse off then reapply but put straight through, i tend to leave cleanse on for 30 mins per application , and depending on strength of hair to how many times i put on, you can do cleanse upto 3 times. i would then do a protein treatment ( i use cat in redken) then i would dry off , your looking to avchieve an orange tone . I would then do 8/0 with 0/88 mixtone with 6% and do balyage with lightener of 10 vol. but to be honest i would recommend your client to come back in two weeks time for lights to give hair a break, as she doesnt want to take her hair home in a bag ;-). when she comes back paint lightener on with 10 vol ( low and slow ) and then tone with 9/71 pastel xx