I have a very similar doorway as yours, I used four curtains, two side by side on the outside and another two side by side on the inside, the dual curtains really helps and blocks 99% of the light out of my room. I just realized I dont have any pictures of my entry in my build thread, I will try and take some for you tomorrow. My curtain rods are probably only about two inches above the opening, most important is that you extended the rods long enough on the sides to allow the curtain to overlap the walls enough to not let the light seep through.