When the need to reef arises is is very important that the sail shape be held as flat as possible. A double braid dacron line may feel tight upon initially putting in the reef, but the line will stretch under load changing the shape of the sail.The key ingredient is low stretch (not size). Spectra lines are much lower stretch than double braid and are very much stronger. For that reason you can down size when switching to spectra which lowers the cost while producing a better sail shape.I would recommend a striped 1/4" spectra line w/cover on the part you handle.