The class legal 8:1 cunningham lets you crank up the class legal dacron sail enough to sound like a nice snare drum. That's what we ran on our 18.

IMHO, 8:1 is not enough DH purchase to make playing it from the wire a reality. I've raced all the Hobie classes (except 17) and think you're kidding yourself pretending to go upwind like a Tornado, N20 or F18. The 8:1, and less, allowed by Hobie rules is not enough purchase to make the DH anymore effective than a set-it and forget it function a on "class legal" Hobie boat.