It's worth remembering that the way genetics work, bloodlines mix all the time and family trees thin out a blood line at a scale of 2^n generations. Families are messy things on top of that. Does the curse spread out exponentially with the same power as the first generation or two? A curse from 4 generations back would only net me 1/16th of the blood, so 1/16th the curse? or does the curse follow one randomly selected person in the line and descend with them generationally? Is it like trying to inherit land always split between siblings? Or a recessive genetic trait, like red hair or blue eyes that shows up rarely in a generation?
I can't speak to technique, but anecdotally, in a deep meditation I had a vision of someone cursing a distant family member and a horse falling and crushing their right leg being part of it. A lot of pain and hate released in that event, and it seems more like a natural curse from deep in someone's rotten heart, rather than a ritual or spell. Could also be my brain totally making things up, so who knows, but it was me trying to get to the root of why my leg falls asleep in certain positions.
Which, if that's the curse still left over, it's more like a lame and diluted spirit attachment than anything else. Relative to that side of the family that's doing pretty well all things considered, minor annoyance at worst. Personally, I think it's something my brain made up and it's just the way my nerves run in my legs isn't suited for certain sitting positions.