I happened to be writing a paper for a history course concerning the JFK shoot shortly after the Ayoob article concerning the lefty shooters came out. I, too, shoot lefty altho I am right handed, due to left eye dominance. Oswald was known by some, including his brother, to shoot lefty. Conspiracy theorists like to point out that the scope on the Carcano was set up for a lefty, as well. 1+1=2, no? Additionally, the angle was difficult for a righty, yet ideal for a lefty, which explains why he didn't shoot the "easier" oncoming angle.
Further, only two shots were hits, the first shot missed and hit near a curb, most likely due to the shooter's excitement. The second shot hit Kennedy in the back of the neck and exited through his tie knot, which constricted the flesh so that that exit wound looked similar to an entrance wound. (Much of the info on wounds was found in various JAMA articles on the subject.) This same bullet, the so-called "magic bullet", passed through Kennedy's neck, deflecting slightly off his vertabrae, then on to hit Connelly in the back, through his tie (you can actually see the tie move on the Zapruder film) into his right wrist which was pushing against his left thigh as Connelly turned to look toward the sound of the shots, then stopped in his thigh. This bullet, an FMJ, had a higher sectional density than the 7mm bullets Bell used to kill elephants. BTW, Kennedy's vertabrae wound caused his hands and arms to involuntarily fly up, looking like he was clutching his throat. There is a medical term for this reaction which escapes me now, but the reaction is clearly visible on the Zapruder film. This wound to the neck would have left Kennedy paralyzed, if not dead, according to the medical journal articles I read.
The third shot was the head shot. A man named Lassiter investigated the Kennedy shooting, and published several articles on the subject. He even obtained human skulls, filled them with ballistic gelatin, and shot them with Carcano's at the same range and angle as the head shot. The skulls were sitting on a stool. All the skulls were blown back toward the shooter by the evacuating gelatin.
Oswald could have made the shots, and the shots he could have made would have made the same types of wounds.
Finally, if Oswald didn't shoot, why did he leave the building, go change his jacket and grab a .38 revolver, and head downtown where on the way he shot and killed a police officer. Then he was apprehended inside a theater with the revolver, which he had reloaded at the scene of the shooting. Interesting behavior for an innocent man.