Do what you are comfortable with. How do you know what size stones you have? Your ducts might just have sludge and sandy type stuff in it. Did you have an ultrasound? When people are talking about stones they are usually soft cholesterol ones, like green peas or smaller.
When they are the size like a double bean you can't even feel them come out. The butt pee, from the Epsom Salts , blows everything out and you only feel water.