Well, out of the blue, I decided to do a flush last night and it was by far the most productive; flushes no 1,2, & 4 did not yield stones but this one yielded 3 huge rocks (biggest one about 1in diameter ball) among a couple of small ones so far. No sludge.
I did not prepare in advance, although i been having my apple a day for the past week, and had gcg and chinese bitters yesterday morning; the biggest difference is in the juice; I mix 1/4 cup grapefruit juice with 3/4 cup olive oil and chased it with 1/2 cup of lemon juice; I think the acidity of the lemon aided in the flush somehow. Or perhaps is close to the new moon.
Mike