Gotcha.

I would think that is a good place to start. you can test it out on the beach when you get your mast up. Have someone sit on the other hull of your boat (as to not tip it).

I would suggest you be able to clip on and off while sitting on the tramp but when out on the wire, keep it adjusted so your butt slightly above the deck as a starting point.

You say you have a ball as a stop? If this is held in place with a knot, I would suggest the little black stops as they are easly adjusted while on the fly. They can't cost more than a few bucks. Althoug the Tornado guys simply tie a knot to save the weight of the plastic stop (1.5 gram?, lol)