I experimented with this simulation and I found The easiest way to hit JFK was to first hit the driver of the limo, which causes the limo to stop. Then it’s a 2nd shot at a stationary JFK which is almost a certain head shot kill, because the scope of the rifle is accurate (unlike the poor quality scope of the real MC rifle that was found on the TSBD 6th floor , which was also completely out alignment).
IDK if shooting Greer, the limo driver would have worked in the real situation, but the program of this simulation seems to presume the limo would stop with the driver hit, even if he is just wounded.
Greer getting wounded on the other hand might of reacted by heroically stepping on the gas and driving out of immediate zone if danger.
Or.. he might have failed to react as in the actual assassination, and almost stop the vehicle instead of immediately stepping on the gas.
I found that Attempting to hit the JFK model while the limo was moving was much more difficult even with the scope accurate. But I’m only an average shooter, not an expert, probably about the average type of shooter Oswald was on Nov/22/63.