I'd highly recommend the OP take Charles Cotton's Use of Deadly Force class to become better educated on these issues than is possible in a CHL class.
I'm no lawyer and this is NOT legal advice, but I do teach CHL classes so I'll walk you through various legal justifications as I understand them.
Ruark wrote:(1) Some guy walks up to you and makes physical contact: he starts trying to shove you around or grab your shirt sleeve or paw your wife. You push him away and he just comes back and won't stop. Maybe he's high or has had a few drinks. But he's apparently not armed. Would the law find me justified in, say, exposing my weapon and telling him to back off? What about pointing it at him? If, after that intervention, he continues, what about actually SHOOTING him, at least maybe in the knee or foot?
Let's look first at what "crime" the guy may be committing against you. From your description, I'd describe this crime as a "simple assault" , likely PC 2201 (a)(3) (as opposed to aggravated assault which would require actual serious injury to you or the use of a weapon by the assaulter)
Sec. 22.01. ASSAULT. (a) A person commits an offense if the person:(1) intentionally, knowingly, or recklessly causes bodily injury to another, including the person's spouse; (2) intentionally or knowingly threatens another with imminent bodily injury, including the person's spouse; or(3) intentionally or knowingly causes physical contact with another when the person knows or should reasonably believe that the other will regard the contact as offensive or provocative.
So your response to this, let's start with whether any response at all is justified:
Sec. 9.22. NECESSITY. Conduct is justified if:(1) the actor reasonably believes the conduct is immediately necessary to avoid imminent harm;(2) the desirability and urgency of avoiding the harm clearly outweigh, according to ordinary standards of reasonableness, the harm sought to be prevented by the law proscribing the conduct; and(3) a legislative purpose to exclude the justification claimed for the conduct does not otherwise plainly appear.
From the above, I'd say you have a desirability and urgency of avoiding continued harm ...
Now let's start with the strongest possible response - "actually SHOOTING him" which is a definite use of deadly force:
Sec. 9.32. DEADLY FORCE IN DEFENSE OF PERSON. (a) A person is justified in using deadly force against another:(1) if the actor would be justified in using force against the other under Section 9.31; and(2) when and to the degree the actor reasonably believes the deadly force is immediately necessary:(A) to protect the actor against the other's use or attempted use of unlawful deadly force; or(B) to prevent the other's imminent commission of aggravated kidnapping, murder, sexual assault, aggravated sexual assault, robbery, or aggravated robbery.(b) The actor's belief under Subsection (a)(2) that the deadly force was immediately necessary as described by that subdivision is presumed to be reasonable if the actor:(1) knew or had reason to believe that the person against whom the deadly force was used:(A) unlawfully and with force entered, or was attempting to enter unlawfully and with force, the actor's occupied habitation, vehicle, or place of business or employment;(B) unlawfully and with force removed, or was attempting to remove unlawfully and with force, the actor from the actor's habitation, vehicle, or place of business or employment; or(C) was committing or attempting to commit an offense described by Subsection (a)(2)(B);
I see no justification above for shooting someone over a "simple assault" as you couldn't yet be in actual fear of death or serious bodily injury (in your description he's shoving, grabbing, pawing - not striking, hitting, or pulling - as if trying to pull you away, like into a van for a kidnapping or something). And it does not seem from your description that any of the crimes in 9.32 (a) (1) (B) are yet being committed or threatened - closest would be robbery, but no theft has been attempted or threatened in your description - so can't be robbery yet.
Now let's go to exposing your weapon or pointing it at him (which I THINK are basically the same thing under the law) - both are a threat to the other person. Question is whether you are justified in making that particular threat.
Sec. 9.04. THREATS AS JUSTIFIABLE FORCE. The threat of force is justified when the use of force is justified by this chapter. For purposes of this section, a threat to cause death or serious bodily injury by the production of a weapon or otherwise, as long as the actor's purpose is limited to creating an apprehension that he will use deadly force if necessary, does not constitute the use of deadly force.
This would seem to give you justification, as long as you meet the use of force justification:
Sec. 9.31. SELF-DEFENSE. (a) Except as provided in Subsection (b), a person is justified in using force against another when and to the degree the actor reasonably believes the force is immediately necessary to protect the actor against the other's use or attempted use of unlawful force. The actor's belief that the force was immediately necessary as described by this subsection is presumed to be reasonable if the actor:(1) knew or had reason to believe that the person against whom the force was used:(A) unlawfully and with force entered, or was attempting to enter unlawfully and with force, the actor's occupied habitation, vehicle, or place of business or employment;(B) unlawfully and with force removed, or was attempting to remove unlawfully and with force, the actor from the actor's habitation, vehicle, or place of business or employment; or(C) was committing or attempting to commit aggravated kidnapping, murder, sexual assault, aggravated sexual assault, robbery, or aggravated robbery;(2) did not provoke the person against whom the force was used; and(3) was not otherwise engaged in criminal activity, other than a Class C misdemeanor that is a violation of a law or ordinance regulating traffic at the time the force was used.(b) The use of force against another is not justified:(1) in response to verbal provocation alone;(2) to resist an arrest or search that the actor knows is being made by a peace officer, or by a person acting in a peace officer's presence and at his direction, even though the arrest or search is unlawful, unless the resistance is justified under Subsection (c);(3) if the actor consented to the exact force used or attempted by the other;(4) if the actor provoked the other's use or attempted use of unlawful force, unless:(A) the actor abandons the encounter, or clearly communicates to the other his intent to do so reasonably believing he cannot safely abandon the encounter; and(B) the other nevertheless continues or attempts to use unlawful force against the actor; or(5) if the actor sought an explanation from or discussion with the other person concerning the actor's differences with the other person while the actor was:(A) carrying a weapon in violation of Section 46.02; or(B) possessing or transporting a weapon in violation of Section 46.05.
Looking at 9.31 (b) I can see a case to be made for justification, but again because this is just a simple assault at this point it doesn't meet the more stringent list of crimes that could give you more solid justification by being "presumed reasonable" if the other had been commiting a more serious crime or had been committing the crime while illegally inside or attempting to enter with force your home, car, etc.
So if we stop at this point, I think you COULD be justified in exposing your gun as a threat to back off. But there is one more piece of this puzzle that makes it even more dangerous for you to "go to guns" in response to this simple assault.
Because you're not in your home, the assumption is this assault takes place in a public place. Thus you MUST be carrying your gun under authority of your CHL (you're not at home, in your car, or in your workplace - the requirements to carry without a CHL in Texas).
Sec. 46.035. UNLAWFUL CARRYING OF HANDGUN BY LICENSE HOLDER. (a) A license holder commits an offense if the license holder carries a handgun on or about the license holder's person under the authority of Subchapter H, Chapter 411, Government Code, and intentionally fails to conceal the handgun.
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(h) It is a defense to prosecution under Subsection (a) that the actor, at the time of the commission of the offense, displayed the handgun under circumstances in which the actor would have been justified in the use of deadly force under Chapter 9.
PC 46.035 makes intentionally unconcealing your handgun a crime while carrying under authority of your CHL and the ONLY defense to prosecution for this is if you were justified in using DEADLY FORCE - not merely FORCE - under Chapter 9.
As we've already established above, you weren't yet justified in shooting the person, so if you even expose your gun on purpose as a threat you COULD be guilty of violating PC 46.035 (a)
Ruark wrote:(2) Same thing, but he doesn't make physical contact. He's following you and making verbal threats and trash talking and making demands, even though you try to ignore him.
I'd say you have even less justification than above if no physical contact is made. And the verbal threats alone do nothing to support a use of force justification, much less use of deadly force.
Ruark wrote:Of course, we've all heard the example of the little old lady who would be justified in using deadly force against a big thug. I'm not a little old lady. I'm a 6 foot, 220 pound dude, but I'm 61 years old. I'm not a cripple by any means, but I stopped being 25 a long time ago...

I can understand not blowing somebody's head off just for trash talking you, but at the same time, I resent the fact that I might be REQUIRED to get into a knock down, drag out, John Wayne fistfight with some punk, just because he's unarmed.
We've heard all the reasons why deadly force might be necessary one or both of those situations, but I'd like to know just how far Texas law goes in protecting you and saying what you can and can't do. Can anybody clarify?
As above poster stated, "disparity of force" can quickly change the use of force/deadly force hierarchy in favor of using more force. If there is an accomplice watching closely what the assaulter is doing to you, if the assaulter is much younger and more physically fit, you may be justified more quickly and easily in using force.
None of this, of course, gets around PC 46.035 UNLESS you can justify a use of DEADLY force. For that I think you'd have prove the assaulter was trying to a) rob you b) severely beat or kill you, with the understanding that depending on the disparity of force from age, size, physical prowess, a single strike to the head could cause you serious bodily injury - basically a broken bone - or even death from blunt force head trauma.