Cosmetologists!! Has anyone used the 'green village collection' in the Shades EQ??

I was curious what the 06gn and the 08gn really do. I'm new to the line. My sister has level 6 red/auburn hair naturally. She wants to go to a level 5 brunette without hi-lighting (her hair has been through a lot this last year). Any Shades combo we do pulls a lot of red still...which she wants to tone down. The literature says the Shades gn line helps diminish red/orange tones. I'm nervous to try. Will it help will natural red hair?? Whould you use it alone with the processing solution or combine it with something like 6n for example?? Please let me know. ThanksQ