If I use 2 bottles of hair color, will the color distribute more evenly?

So my mom normally dyes my hair for me and its always really uneven. Either she doesn't do it right, or its because I only use 1 bottle of hair dye. I do have pretty thick, long hair. If I use2 bottles this time, will the color be more even? and im dying it deep burgundy. The shade on the box is 42R. Right now my hair is dark brown with some burgundy from a previous dye mixed in. with blackbrown underneath. If I use 2 bottles will that make my hair come out really bright burgundy?