I've never done a re-surround, but seems to me that shimming would center the voice coil and thus enable the re-surround most accurately. Otherwise, if you glue the surround to the cone first, let dry, then apply the glue to the frame, followed by pushing the surround into the wet glue while the driver is perfectly level, it seems that would be a good method.
Perhaps someone else has done this successfully?:help: