If you prefer to use TurnEntity then you can use the EntityPitch, or EntityYaw, or EntityRoll commands to find out the current state of the entity.
Or you could just use the RotateEntity command and then you would automatically know what rotation the entity is at since you are the one setting it.
Or you could just use the RotateEntity command and then you would automatically know what rotation the entity is at since you are the one setting it.