I have no experience trapezing off a mono haul but i have been trapezing on a hobie cat for a few years. I bought a hobie harness right off the bat and didn't consider any other harnesses. after seeing the gill ones I regretted my choice. heres a link to lots of good harnesses http://www.apsltd.com/c-3825-trapeze-harnesses.aspx good luck
420 racer: Just be really safety conscious. A girl of about your age died recently in the Annapolis (MD) area while trapezing on a 420. Although the exact reason for this tragedy has yet to be formally documented, it appears that she got trapped under the boat after a downwind death roll and drowned because she couldn't free herself. All this happened during a high school practice, supervised by an experienced coach.