If you just have stones or sludge, you don't necessarily need the walnut hull tincture. If you are doing a parasite cleanse, then you will need this. Of course, they do recommend you follow the protocol completely, but I have done Liver Flushes 4 times without ever doing a parasite cleanse.
PS: if you want to discuss liver flushes, you should post on the liver cleanse forum. You'll get a lot more replies there.