I´ve done 20 flushes and in my experience it works like this: The first flush tends not to push many stones, mostly because your liver is likely to be congested. Second or third flushes are usually successful and push small stones, or mostly small stones. As the stones you´ve pushed are the ones which were in the front of your gallbladder, the ones located in the back will move forward and will be pushed in the next flush. The ones in the back of your gb tend to be larger as they are older.
In short, the first flushes tend to push smaller stones and later the large ones come out.
But remember that every flush is different and unique and therefore, one should not be frustrated or sad when a flush does not seem to work. Sometimes one flsuh does not work so well then we do another and the next one is fantastic.
Flushing requires discipline and is a long-term treatment.