Here´s a link of a recent interview with more insight on his racquets, it´s in spanish sorry you´ll have to translate..
http://espndeportes.espn.go.com/blogs/index?entryID=1883715&name=juan_ignacio_ceballos&cc=7586
http://espndeportes.espn.go.com/blogs/index?entryID=1883715&name=juan_ignacio_ceballos&cc=7586