Coloring gray hair

Today I have to recolor someones hair. Originally she told me she wanted a color weave with blind and brown. She did not want her hair to be gold or red in any way. Yer hair is very curly , coarse, and gray. I alternated foils 1) chi bleach 20 vol 2) 6n age beautul 20 vol . After I was completely done she said the hairdresser she went to before never left hair between the foils. So now I have to redo it and make the rest of her hair blonde she doesn't want to see any gray at all. Wish my consultation had been better , so how to I color all the gray with hair color not bleach and not mess up the brown and hilites? It would take all day to pick those out and wrap them in foil before coloring the rest of the hair. And what's a good formula to use on the gray to make it blonde ( no red or gold )