Hi, client has 95% white hair (3inch roots) with the rest level 7. Lifted hair with colour remover and developer. Used Wella naturals 9/0 + 9/38 (50/50 ratio) with 6% developer. The roots were not properly covered. Is this because level 9 is too light for 95% white hair? Am wondering whether to redo in the level 9 or use 8/0 + 8/38. Outcome required is a soft golden blonde. Any suggestions welcome.