I used some Vallejo model air Fire red and some Vallejo model air tank brown. I mixed like Red to brown 7:3. Something like that. you want more red and a little brown.

I used it on this tank right here. I needed a TAD bit more red but it came out GREAT for a first time trying redoxide!!!!!!

http://www.scalemodeladdict.com/forum/index.php/topic,3616.0.html