hi
my h-16 has a single reef (%??) points are in the middle of the first and second lowest battens. i just reattach it into the goose neck like the original foot, and tie the extra sail to the boom with some extra line.
works great when you need it. i've used it twice or 0.01% of the time so it's kinda useless. i have better luck just sailing very safely, unstead of trying to fly a hull in 35 knots.