All I can tell you is what I do (and it works for me).
I take 60 drops 2 x a day 4 - 5 days before doing a flush. I also drink a gallon of apple juice (thanks for that figure, Shelley) in that time. I eat lightly (you won't feel hungry with all that Chancra Piedra, water and apple juice, trust me).
I have done two flushes now (wow -- and old timer ) and have done the same thing each time.