First I will say that I beleive in pressure points having seen, felt and used them. So I am not downgrading them, or doubting those that train with them. If you put the time, and effort into it, showing your dedication, I say God Bless You!
Some points to consider in terms of realism. Keep in mind that I'm not trying to ruffle feathers, but, just trying to help out, as I've seen the "Training theory" people in action constantly, and have seen the results.
The fact that your posture having to be correct is everything shows it's weakness in terms of reality. Nothing is everything due to the fact that nothing is or remains constant. What comes the closest to everything is BALANCE. If you are off balance everything else: posture, strikes, etc.. goes to crap. (It applies mentally, and spiritually as well). This is your flaw. For real, your attacker decides where, when, and how the event will go down. You will be caught off balance, no matter how hard you train!
Also consider another reality: Hardly anything ever goes the way you train for-- too many variables, none or very little of which you'll have control over, also those variables keep changing, second to second.
There's also a person's physiological responses. They are different for each person, add to it drugs and alcohol, the chances of pulling PP's off decreases.
There are correct angles etc.. involoved in using them, correct posture or not. Bad idea to get into a fixated mind set of targeting those little dots on the body. People get ears ripped off, groins destroyed, noses broke etc.. and keep fighting. Those are big areas to hit, and they are difficult to get to for real by themselves.
For the sake of reality, keep it simple and straight forward!
Everyone be safe!