I'm making a male torso cake and he needs to be brown. Trouble is that I'm out of brown gel color. I'm using red, blue, and yellow to get brown. My first sample came out perfect, but when I tried to make a larger batch, it's coming out kind of green. Should I be using equal amounts, or use less blue. Please help.

Honestly I would take the time to make a trip to the store for brown color gel.  Consistency is important and even if you get the color you want the first time you may need more and end up with something different.

If its coming out green add more red.

ADo you have any ivory?

Ivory makes really great flesh tone

Cocoa powder or melted chocolate?

I'd suggest ground cinnamon and cloves, but I don't think I will suggest that (or at least suggest it by itself), because enough to get a real brown would also produce a very spicy taste (and probably wouldn't be healthy to eat, either)