Then how can the magic bullet have struck Kennedy's back at a 45 degree downward angle and then go out higher at the throat and then strike Connaly at a 39 degree downward angle?
You assume they were both sitting perfectly erect in their seats at a 90 degree angle. Think about the effect if one or both of JFK and Connally were not sitting perfectly erect. Each degree variation from the vertical produces a corresponding change in the bullet path through the body.