I don't see Pat Speer agreeing with you. He disagrees with the Lattimer, Posner, Myers (LPM) theory of the shot times (which posits an early missed first shot) but doesn't say that the witness evidence supports only two shots. This is taken from his site:

Seems like Speer agrees with me that the first shot didn’t miss. That was the main thing that I disagree with other LNs on. I don’t think there is much disagreement between me and other LNs that JBC was struck in the torso on the second shot and JFK was struck in the head on the third. So the only thing that other LNs and I disagree on is something that you, I and Pat Speer agree on: that the first shot didn’t miss.
Speer does not agree with you. You could not even read his website; you even failed at that. Your theory fails at every level and standard of understanding. It has been proven over and over and over again, but you do not listen to or attempt to at least track the reasoning behind the explanations.
I am unimpressed with who thinks what. Three shot narratives of any and all forms have failed to produce any concrete answer to the assassination, so on and on it goes. In 63 years of study of the JFKA only Josiah Thompson has made a certifiable contribution to the understanding of the assassination. Even then, with his observation he could not help himself but add another shot from somewhere else.
You seriously follow up one summarized witness table with another summary of witnesses. Are you really this lazy and unimaginative? Pat's summary you posted is not even a tabulation of his own analysis of the individual witnesses. That point did not strike you as odd or are you so incapable of individual thought and initiative that you did not notice.
The 50 two shot eyewitnesses and the 20 eyewitnesses who claimed to have heard a third shot after the headshot are listed on Pat's website where he did a great service by collecting all the information and locating it in one place. If you are interested, you will find them there. If you are lazy and want someone else to do your thinking for you then continue posting the sorry HSCA compilation.