I really liked Garnier Nutrisse. It covered very well. But I wouldn't use it on relaxed hair. For relaxed hair I love Bigen.
As far as the hair turning green...I think you have to use a filler before ...I don't know if that's the right word. But I remember the very first time when I went to the salon to get Bigen applied my hair was highlighted and the stylist told me she had to use a filler so my hair wouldn't turn green after shampooing it several times.