Find some with a forehand grip clearly visible that tell "your side of the story" instead.
A FH volley grip will do as well.
In the pictures you post he's not even gripping the racquet and you're telling me his handle "looks smaller than your 3/8".
Well...of course it looks small next to his body, he is HUGE.
You said you were 5.11, he is 6.4. Understand the difference ?
Same logic was used to state that Berdych's old Dunlop frame looks like a mid size, when it's in fact a 97-98 sq inch. Of course it looked like a midsize in Berdych's hands...the same frame would look close to oversize in Henin's hands.
Trust me ... I don't really care what grip size he used/uses enough to "find a picture that backs up my argument"...I just looked for one where it was clearly visible how he gripped the racquet...so that we have some reference point.
Your pictures have no reference point.
Here's the best I could find from the 96 French Open. It's a serve, with a continental grip, and I see his overgrip between the fingers and palm.
I can't be bothered to look for more...do it yourself if you want. Keep in mind HE IS 6.4
. Safin is also 6.4, uses a 1/2 grip and his fingers look to be touching (or close to touching) his palm most of the time (certainly in the continental grip he uses for serves).