There's a lot there to talk about at that link, much less refute in the limited space here. Nor do I have the wealth of arguments available at hand to extensively refute everything there. Volumes have been written arguing both points of view. However, this graphic says it all:
For Connally to be hit by the same bullet he would have been sitting much further to the left when he turned to look behind him.
I don't believe Oswald was the lone gunman. But I do think he was one of more than one gunmen. I also think he fired at least 2 (of a possible 4) shots at Kennedy, at least one of which hit Kennedy. Probably the one where he holds his throat. I think he probably missed JFK and hit Connally with a second shot. However, I think the headshot came from another gunman standing behind the grassy knoll.