My first Clark flush I had some marble size stones with many pea sized ones. The next flush I had pea size stones. The final time I had only green bile so I figured I likely was finished flushing stones. That was a long time ago 2 or more years.
One thing I didn't like about the Clark flush was the nasty epsom salts drinks. The oil and Grapefruit tasted good (yummy) because I was starving.
I'm now getting set for the Coke flush this weekend. Seems easy. I'll just eat a light dinner so the oil won't bother me. And make sure the coke and oil are mixed all the way.
Sutter probably says not to shake it because the Coke could still have enough carbonation to boil over.
If you have a bad flush you may still be moving the stones closer and flushing out other garbage.