He really was an impressive man on a lot of levels. Partook in a variety of different sports in youth and seemingly excelled at all of them. Had an excellent boxing career. Knew a lot about the outdoors and (probably ) farming. Then later started a small boxing venue which hosted fights. Believe he lives until he was around 70 which was somewhat of a long life by the standards of when he died
Not really because I don't think Jeffries put the sort of sustained ,"in your face ",pressure on a man as did Marciano.
But film of Jeffries actually fighting Ruhlin shows no head movement.He just advances slowly with his left hand down by his waist and the left side of his head exposed.
To me, it seems like Jeffries tries to make up for his left hand by crouching to his right side, keeping his right hand up to parry and keeping his chin dug into his left shoulder. Schmeling for example also liked to keep his left at waist level and depend solely on his right hand to parry punches, similarly to Jeffries in the Ruhlin clip and his stance in his picture: https://npr.brightspotcdn.com/legacy/sites/wmky/files/201904/350px-JEFFRIES09.jpg