the halyard extension wont work. there has to be a attachment point directly at the head of the reefed sail. or it will blow out of the luff track. from what i understand, use the same hardware that holds the head of the sail. in the h17 case, there is a hook, i will rivot on another lower. hopefully the prindle has a hook? i think the order of things would be: 1. have reef points added at some percentage of the sail. 2. mount the hook according to the new sail height. what % should i have the sail cut???