Zipping shouldn't be a problem, they say that they have a continuous line that goes up to the head of the sail, so in theory you pull the line along the boom and it zips up to the mast.
The boat currently has a Mackpak that has seen it better days and the sail spills out over the sides of the pak and the zipper is hard to move.
I think that the cradle makes more sense because the lazy jacks are attached to the upper part of the cradle which should help to prevent the sail from spilling over, where as the Mackpack jacks go under the boom.