I'm doing a 3 tier cake to look like drums. The sides of each layer will be silver. I'm doing 12, 10, and 8 inch rounds. The luster dust will be mixed with vodka to paint on the fondant. About how much luster dust do you think I would need for all three cakes? And is there a ratio you use of vodka to luster dust? I've used it all before but never for such a large area.