Use 7/16" StaSet double braid for my large main. Easy to hand and not overly large and bulky. 1/2" just seems to take up a lot more space when coiled than 7/16". Would use 3/8" if it wasn't so hard for my stiff fingers to grab. Want the stretch of Dacron so the clew doesn't rip out in gusts. Would rather have the rope
take the weight of the gust rather than the sail material. Line is easy to replace, a ripped main is another story. Besides, double braid is half or more in cost than the exotics. FWIW, have double line reefing lead back to the cockpit. The shortest clew reef line is 40' so plenty of line to stretch but have had no difficulties.
As far as wear, it's not that big a deal. Have used dacron for reefing lines while cruising with very little chafing at the cringle. Just shortened the line a couple of inches after 10,000 miles of open ocean sailing with much of it reefed. On the passage
back from Tahiti
, had the second reef in for 6 days and a thousand miles in gusty trades 25-30k. Didn't have significant wear after that passage