Geneva Hine gives her testimony to the Warren Commission on April 7, 1964. If one reads her testimony and relates it to the second floor plan of the TSBD, it is apparent that she is looking out the east window of their office (overlooking Houston Street) as JFK’s limo is traveling north on Houston Street and turning west on Elm Street. She would not be able to follow it any further than when it disappears behind the southeast corner of the TSBD from her point of view.
Here is a relevant part of Geneva Hine’s testimony:
Miss HINE. Yes, sir: I was alone until the lights all went out and the phones became dead because the motorcade was coming near us and no one was calling so I got up and thought I could see it from the east window in our office.
Mr. BALL. Did you go to the window?
Miss HINE. Yes, sir.
Mr. BALL. Did you look out?
Miss HINE. Yes, sir.
Mr. BALL. What did you see?
Miss HINE. I saw the escort car come first up the middle of Houston Street.
Mr. BALL. Going north on Houston Street?
Miss HINE. Yes, sir; going north on Houston Street. I saw it turn left and I saw the President's car coming and I saw the President and saw him waving his hand in greeting up in the air and I saw his wife and I saw him turn the corner and after he turned the corner I looked and I saw the next car coming
Just at the instant I saw the next car coming up was when I heard the shots. Mr. BALL. How many did you hear?
Miss HINE. Three.
Mr. BALL Could you tell where the shots were coming from?
Miss HINE. Yes, sir; they came from inside the building.
Mr. BALL. How do you know that?
Miss HINE. Because the building vibrated from the result of the explosion coming in.
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Mr. BALL. That is when you were at the window, is that right?
Miss HINE Yes, sir; that is when I was at the window,
because the next car, you see, was coming up and turning and I looked.
Geneva Hine doesn’t specify which car is the next one. I therefore have to speculate that it would either be literally the next vehicle (the presidential follow-up car) or possibly the Vice Presidential vehicle. The presidential follow-up car was only a few feet behind the limo at this point. And there was a significant gap between it and the vice presidential car. So, I suspect that she is describing the vice presidential car. Either way, Geneva Hine’s testimony is that the shots began very soon after the presidential limo disappeared from her point of view behind the southeast corner of the TSBD.
Looking at an animation that shows an overhead view of Dealey Plaza and the locations of the motorcade vehicles as they progress through the plaza area, it appears to me that at the time frame around Z133 the vehicles that Geneva Hine describes would be about where she says they were when the shots began. I will post an image of this here shortly from another computer.

It appears to me that Geneva Hine can be added to the list of witnesses who’s accounts support a first shot around the Z133 time frame.