I don't have any specs, but the sheet for a 155% jib should be about 150% of boat length. The Lewmar 40 self tailing winch can accommodate a line size between 5/16" and 1/2". With jib sheets, it is more about a comfortable size which is friendly to your hands than breaking strength of the line. If I ever had to replace mine, I would get 7/16" x 50 footers.
Dave on Valcour #219