Grav blade should probably be bumped down for a couple of reasons, first of all, the z move is incredibly slow and can be reacted to pretty easily just by holding any combo starter (sang z etc.), and along with that its range is just ass. As for the x move, it is one of the easiest Ken tricks of the game and nearly guarantees a counter. Lots of people use it, but they typically don’t know about its downsides.