One of the optional Wave sails is a Main w/Zip Spirit. I assume that the Spirit is a smaller subsection of the Wave's main sail for use in heavy winds. Would you recommend the zippered main or a separate Spirit sail?
Spirit is the color. The zipper setup is a modification of the standard sail, to allow for reefing. You un-zip the lower panel. You lower the main and tie off the halyard for a smaller sail to be used by kids or in high wind.
Unless you are light or sail in very high winds, I don't think you need it. The Wave is underpowered and comes alive as the wind increases. If high wind is an issue, I recommend the main traveler system.