Has Henry Mallard started calling himself Hank? He's been a great promoter/supporter of our class and owns a J/30 (though regrettably for sale). I think you don't want your mainsail or your halyard to stretch. Your main is getting worn out by tacking (which you can't avoid) and luffing in high winds. Double braid poly is fine for control lines and sheets, but I wouldn't turn the clock back to the 1980's and use it for a main or jib halyard. Super high tech line is overkill unless you wish to handle dental floss. Try a Dyneema/Spectra core with a poly cover. Gordon Latrobe (Shaken not Stirred) made us a set using Samson Warpspeed 3/8" for the main, 5/16" for the jib. He also installed a nice set of lifelines on Bebop. Gordon's rigging company is at 410-626-8855 www.northernbayrigging.com.