My natural hair color is black level 2 w/VERY strong red undertones, and it is very hard to lift.  It usually takes a few hrs at the salon.   I would like to get my hair to a light ash brown.  My hairdresser just moved out of the area, but she gave me my formula before she left.  It was 9n with a drop of 6nb.  Although I liked the color, it was still too warm for me.  By reading another post, the coolest color combination is ag.   I just learned of the new Redken Double Lights for Level 1-5 hair.  Looks like the lightest shade is the 10ab, but there is no 9ag or 10ag.  I was thinking that the 10ab would work just as well at cutting out the red/orange/brassiness? If not, any suggestions on what would work better?

Also, after my hairdresser colors my hair we also have to use a toner to cut out the residual brassiness. But, she didn't tell me which toner she uses.  I looked at the Redken Shades EQ, and I am thinking that the 9n would cut out the most red/orange/brassiness.  Any help or suggestions would be greatly appreciated.  Thanks in Advance!

Redken EQ 9N is a brown + blue/violet base. It cut the strawberry in my hair well! (note the difference between the 2nd and 3rd pics in my sig).

As far as your roots....maybe someone else can chime in. I'm not much of a black/brunette expert.