I started with about 12 norton bare roots 8 years ago. When pruning in the spring, I choose the most promising prunings, and propagate. I've increased the size ov my vineyard to right at 50 vines since then, just by rooting cuttings. I have had best luck with what are called "hammer" cuttings, and dip in rooting enzyme and keep indoors till they are doing well, then heel them in the first winter and plant in spring. I have had years when I've had better than 50% growth from cuttings. Just lucky I guess!