I think Joseph meant to say that the size of the garment needs to be 24 inches according to the Chazon Ish. According to R’ Moshe TZATZAL it is 21.25 inches and on can be machmir up to 23 inches (http://www.hebrewbooks.org/pdfpager.aspx?req=916&st=&pgnum=228&hilite=) and according to R’ Chaim Noeh it is 18.9 inches (http://www.hebrewbooks.org/pdfpager.aspx?req=20888&st=&pgnum=326)
