I have a cake due on Friday in which the 10" base tier needs to be royal blue in color. Since this was a last-minute order I don’t have the time to have colored fondant shipped. What’s the best way to get a true royal blue color – kneading in color and killing my arms or airbrushing? Any thoughts on this would be appreciated. I’m also running low on fondant and don’t want to waste any so what’s the max amount I need to accomplish covering a 10" square?