Hair Help

I recently dyed my hair a lovely shade of red, it's beautiful. I had a really dark brown dye that I applied the red dye to and since my roots are a dirty blonde, I only left the Magenta color on for less than 5 mins so the color isn't so intense on the roots. My question is since my roots are so light and I still want that brown effect, can I mix brown and red together? The red I am using is the L'Oreal HiColor Highlights and contains a small amount of bleach. If I use a chocolate brown and an auburn color with 20 volume will my roots be okay? I am thinking of just doing a strand test to see what the results would be.