Originally Posted by kjango
With that new imput , I'm inclined to go with some modern low stretch 7/16" size line . I like a little something bigger then I probably need that I can grab & pull better.
Shorter boat, lower rig, and looks like less sail area than us. I cannot imagine needing line that large. Your boat, your choice, though. Even 3/8" would be large for your boat, IMHO. Since line prices go up by diameter, there will be a significant cost difference going from 5/16 to 7/16......
Either way, you will like having all-rope halyards.