I have brown hair with grey roots.I bought wella 6rv and wella 6 N to mix together.Is this going to turn out lighter,darker redorpurple?I also am planning to use 20 volume developer?Im afraid.Please help.Also can I use the red dold color correct in the color and can I add a small amount of t14 toner to lighten it?

Why are you going to experiment and mix colors? Of course you are afraid. You are going to screw up you hair. Don't mix. Use one. If you don't like it, wait a week, do another.