I mix KK at the maximum 20% by volume with SG100 and then reduce that 2:1 for use in either guns or airbrushes. If its going in an airbrush I'll reduce it down further as I go, but it depends a lot on what the color is and how much I want it to cover per coat. When you get down to putting the paint in an airbrush there is more to it than just mixing up some set ratio and dealing with the result. You mix up the paint a lot differently if you are putting down ghost flames compared to filling in a solid contrasting color stripe.