"You can't clean a liver with living parasites in it. You won't get many stones, and you will feel quite sick. Zap daily the week before and complete the parasite killing program before attempting a liver cleanse. If you are on the maintenance parasite program, you are always ready to do the cleanse."
OK, if you haven't done any Zapping yet at all, a 2-3 week "hit 'em hard" would be good to be sure that all stages are dead and cleansed and that reinfection is at it's minimum.