OIF Armor Color in M1 Abrams

 i have seen models in this forum depicting tanks and bradleys from the oif theate, what i want to ask is whats the proper ratio of tamiya acrylics that can be used in order to replicate color since tamiya paints are common here in the philippines (there's no model master, testor brand in here, ). ive tried mixing desert yellow, buff and drops of white tamiya acrylics but the result does not even come close.

thanks!