I actually have tried no pull harnesses with Pau and other dogs and had issues. The company I was looking into for service training absolutely refuses to use anything other than a flat collar or in some cases a halter of some sort. I have not seen or heard of other options to teach loose leash walking, other than a prong. I have been working with a new trainer that usually works with large breed dogs and protection dogs. He's had me do some exercises with a flat collar and a long line, reinforcing recall frequently during the walk. When I explained what my personal issues were with balance, and we took Pau out around people, cats and other things she might want to investigate, he gave me training techniques to use. For the most part, she is walks nicely with almost no pulling. When she does pull, it's because she's very distracted and wants to investigate or chase.