Goldwell mixing ratio help!

Hello - I need help please!
My hair dresser told me the colours for my hair but not the mixing ratio...
She told me to use Goldwell Topchic 5NN for grey coverage and 5GB colour + (6% 20 vol) but I don't know at what ratio???

I have mid to dark brown hair with 80 - 100% grey on the roots.

Any help would be great - thanks in advance. :-)

Hi Jodeeh,
Thanks so much for your post. Unfortunately your post was made right before the big July 4th Holiday here in the United States where a many of our visitors reside. Many people may be on Holiday and not checking the boards.

However, hopefully someone will see this and respond very soon. Thanks so much for stopping by.

HB Admin Team