It will take more than one flush, I can promise you that much. But, as to how many flushes it will take you, only your body knows for sure.....but it will tell you.....if you listen.
Normally, the first flush is the most difficult---probably because you don't know what to expect. I know I was SO nervous.
My second and third flushes produced the oldest and biggest stones. It is best to wait 2-3 weeks in between flushes to allow the stones to move forward. Some people flush more often, but unless you are in pain, I would suggest you wait in between flushes. You see, your body has had a "mini-surgery" and needs time to heal, too.
But, flushing out your liver is the BEST thing you will EVER do for your body.