in hook grip ,is there some space between the index and middle finger,or

[DorPwnz]

or you need to keep it as one unit as much as you can in order to make it strong and stable?
i will be thankful for answers
Edit : i've learned its sandwiched so yeah its pretty close ^_^

[waistline warrior]

[Troy May]

Good video. Never thought about hook gripping chins.