I am sure Hill was looking at the back of the car. Hill was focused on getting on the car and not slipping off and being run over by the SS car. Hill did hear the headshot. It was the second shot he referred to.
A shot hitting the signal light pole is fantasy. Purely made up crap in an attempt to length the shooting time span. All the eyewitnesses in Dealey Plaza state JFK reacted to having been hit by the first shot. Kellerman referring to the second shot being the headshot only can be interpreted as the first shot was the shot wounding JFK and Connally.
Below is a link to my thread re Oswald's shot-1 being a ricochet offa the signals.
My estimate of pseudo Z123 or Z113 etc varies over time, but in the end i think i tended to go with Holland's Z103 (or Z105 praps).
But all of thems estimates are identical re pozzy, the pozzy was just past the signals.
https://www.jfkassassinationforum.com/index.php/topic,2862.0.htmlMany witnesses said that the first shot was just as the jfklimo straightened in Elm St or words to that effect.
I found a new witness (Whatley) that said so too.