single suit of sails.
TO me that means you cannot change your sail configuration between races. IE one dayers or two dayers. Start with spin end with spin.
If I were you, I would just rig and then choose to use it or not. Its too much of a pain to rig and de rig it. This way if the wind settles down to a more manageable speed for you, then you have it.
Its better to have it and not need it, than need it and not have it.