I question your calculations simply because it appears to me that you incorrectly have the distance of the running deer competition shots at 330-feet instead of 75-feet.
The distance at z-153 was more like 129 feet, not 75 feet.
But the problem is, if the angular velocity is too great, a shooter can't keep the sights lined up on the target. If the shooter can't keep the sights lined up on the target, even one the size of a human, or a deer, I would expect them to miss at 330 feet. Or 129 feet. Or 75 feet. Even at 75 feet you need luck to hit a target of that size when you can't keep the sights lined up on the target as it moves.
The competitors were shooting at a target much smaller than the JFK limo. How many of the 1908 olympics shots do you suppose would have missed something the size of the limo?
I don't know. But all of the competitors had practice at shooting at a moving target. So even if the answer is zero for the 1908 Olympic competitors, Oswald might miss by more than any of them. He had training at shooting at stationary targets. So Oswald, I would believe, could hit a moving target with a slow angular velocity, like at z-222 or z-312. But Oswald might miss by five feet or more at a high angular velocity target at z-153, which could miss the limousine, since JFK was not sitting in the center of the limousine.
In any case, if anyone can find statistics on what good shooters can do with a high angular velocity shot, of 3.2 degrees per second or higher, at distances of 129 feet, or 75 feet, I would like to hear them. And not just assume that at 75 feet, one is so close, one is bound to hit a human size target, even without being able to aim properly. I don't buy that notion.
in 1950, when an attempt was made on Truman's life, Secret Service agents were firing several shots at the main would be assassin from ranges of around 30 to 40 feet. Using handguns. And all of them missing. Except for one morally wounded policeman who got a fatal hit on the assassin from 40 feet away.
When firing under difficult conditions, like using a handgun, or using a rifle on a target with too high an angular velocity, it's not easy to hit a human size target. At 129 feet. Or 75 feet. Or even 40 feet. Misses are quite possible.