If you need an adjuster in the setup, I would put it on top of the furler. You could clamp one end of an adjuster flat so it fits inside the furler jaws. You will need a large diameter shackle in the lower jaw to provide a place to hook the two bridle wires to. I had this exact setup when I added furling to my H16. It probably isn't critical, so I'm sure it will work for you to put the adjuster on the bottom if that is what you want to do.
Good luck,
Jack