In sngs you will run into similar situaions repeatedly where your opponents will have similar calling ranges so if you really wanted to it would not be hard to calculate some calling ranges and use these whenever you run into a situation that qualifies. But really, you don't need to do this, because if you have played enough sngs, you get an intuitive sense of what Harrington is talking about, so you intuitively know when it is right to push and when it is not even if you do not know if it is exactly mathematically correct. You may be able to squeeze out a little bit more in the long run by calculating every time, but, especially if you are multi-tabling, this tiny added benefit may not be worth the time it takes.
Hope that helps - I was also intrigued by that section in Harrington