move tank on top near cave and let him stay there , the boss has to be and stay high.
whm , blm etc move to center and heal him from there , when ghosts move .. the party moves to the left and go up, heal tank from the left, ghost move -> back to the center heal from below.
Reason is if you tank boss below your party will get the tailswipe wich will wipe the party or at least make it very hard because you gotto heal your own party too.
Works perfectly because none of the party get hit by his tail , because of the difference in height when in the center of the / boss party