you got it
That is exactly correct. My OD 28 has a cruising chute and the lines are each about twice the boat length so one line at 4X the boat length ought to be on the money. By the by look at a whisker pole too. Expensive but worth it in light air for a wing on wing run and the main secured to prevent an accidental jibe. Also give you a little extra time for a "sailing by the lee" configuration.Mike