I found that these videos, when put together, definitively link Oswald to the killing of Kennedy. First off is The Kennedy Assassination - Beyond Conspiracy clips of which are assembled here;
The second source of video was a very detailed recreation of the exact poses of the victims taken from Zapruder film footage, that were mocked up by Anatomical Surrogates Technologies for the documentary JFK: Beyond The Magic Bullet. (full video available in three parts here) While the shot does appear to strike too low, it doesn't negate the fact that the "magic bullet" was nothing of the kind.
theorists will of course come up with reasons why this proves nothing.
Personally I see no reason to continue pretending that Oswald did not
kill Kennedy. If you feel the forensic tests are simply not enough evidence, then I encourage you to pick up a copy of Case Closed. If Posner can't convince you, then no one will.