Making grays from these three transparent watercolors is a fun experiment in subtle variations of warm and cool shadows.
The best example I have seen of this is from Jeanne Dobie's book "Making Color Sing". In chapter two, she has wonderful examples of mixing luminous grays with these three transparent watercolors. You begin by trying to mix a gray that is just as close to neutral equal mixes of the three colors. Then you add just a touch of each other color to this neutral, to make a green gray, a blue gray, a yellow gray, a pink (brown) gray, a purple gray and an orange gray.
The surprise came after, when you took the compliment color in it's pure form and painted it adjacent to that gray. The color just popped out. So the orange peach colors of my flower petals are off set with blue and purple grays.