I want to paint a design on my concrete patio but won't need a large abount of each color I want to use. All I can find are gallons. Is there some way to get around this? Even a quart would be more than needed for some colors. Don't need the expense or the waste. Can you use anything but concrete paint? Would buy one can of white and tint it myself to colors I want but not sure if an additive would take away the "concrete" properties of the paint. Ideas, please.