This pic should hopefully clarify. The "main piece" as I call it has major crevices that are inset and one of the outer-lock pieces. The rest, including all the bottom pieces, are floating. I made the bottom parts in separate pieces because it was easier that way, and made for an easier selection set bake. As for the main…
are these really floaters like separate objects/panels floating above the base geo? Because they look like insets cut into your main geometry. http://wiki.polycount.com/SubdivisionSurfaceModeling?action=AttachFile&do=view&target=subd_floatingpanelinglines.jpg