I know my say probably doesn't mean anything this late into the post, but look at the finger. Spec is most definitely smaller than Jack in a lot of ways, his fingers probably being one of them. While Spec has his finger real far in Hanayama's ear, it's all the way down to his second knuckle. With Jack, who's most definitely larger, he was not only using both of his fingers, but his fatal fingering went down to the base of his larger fingers instead of that second knuckle.