I used 3/8" for the main halyard, jib halyard and the main sheet. The rest are 5/16". Could have used smaller line on the jib halyard but 3/8" line is easier on the hands, and if the forestay ever parts, 3/8" line should hold for a good while. I used double braided nylon and whipped eyes in the ends with fids to clean thing up. If you've never tried this, it's amazing to see the line "eat" itself to form an eye. Takes patience though, I had a big scrap pile after just one attempt!!