How would I do this?

After its installed, dye it. that way your placement is exaclty where you want it..

I'm getting a new weave installed--full weave. I wanted to do two colors in the hair. Similar to the pic below. The only difference is I would be doing a midnight black in the front and top of my hair, and the back and bottom of the hair would be a dark brown or an auburn brown. I want to color the weave before it's installed. I have 8 ounces of hair. Do I just dye 4 ounces the black color, and the other 4 ounces the brown color to get a look similar to the pic below? Or would I dye most of the hair black and only a few tracks the darker brown color?

Thanks