I'm glad that you finally had good flush results after using Black-Walnut tincture. Sometimes, it is difficult to flush well if there is too much hardened, congested bile in the ducts of your liver. In that case, bile flow from your liver into your gallbladder will be blocked and congestion and stones will have difficulty coming out.
To soften congestion in your liver, you can be sure to either fast on apple juice, or drink a lot of apple juice during the day of your flush. The malic acid in apple juice will help to soften congestion in the ducts of your liver so you can release it and bile can flow better. If you still have poor results even after increasing apple juice consumption, you can try using Chinese Bitters and GCG tinctures from http://www.sensiblehealth.com.
They work really well at softening congestion and crushing stones so that they can come out more easily during a flush.