There was a thread last summer called "Power righting pole on NA 6.0" that went into some detail. One reply (#9837) had a close up of the attachment point.

Gary & Rick have done a lot of work to make their systems really function well. If you haven't seen or used a righting pole, your first homemade attempt will likely be ineffective, defective, or both. My first attempt was actually laughable, and I'm lucky I didn't get hurt. Even if you copy one you've seen or used, in my experience, you need to take the time to try it out on dry land, then on the water with assistance. Or, just save yourself the time, and go buy their designs.