I use one color and one f/o at a time and just make more than one candle with it. I make pillars only right now so I'll set up three or four molds, melt, mix, sniff (ahhh) and pour in all four. I'm not picky about how much goes in each one as long as I use all the wax I have ready. When they're cool I do the next layer on each one. It is pretty satisfying when I'm done, turning over four molds and producing four matching (but different sized/shaped) layered pillars. I've also started doing the fancy slanted layers, where you tilt the mold. That's dangerous, I found. The hard way.