Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
I'd guess about two boatlengths if you ever plan on gibing the ansymetrical in front of the headstay, so 55' should be about right. I think 5/16" might be a bit heavy for really light air, but 1/4" would be hard on our hands in anything BUT really light air.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.