[HesseJam]

I think that is a good start. But I have the following problems with it:

1) Do VPIPs reliably converge to their true value after 10-20 hands?

2) How do you monitor VPIPs? PT or just an estimate by observation (he pushed/called 5 times within the last 20 hands)

3) you say that their calling range changes relatively to the grade of their coverage of the stack of the pusher. How likely is it that this grade remained the same with regard to the different pushers during the last 20 hands. Not very likely I think because they will have pushed against different opponents and their grade of coverage had been different also. Alternatively, you would need a coverage-grade related observation over quite many of the last hands. But then, you also have to take into account a wide range of blind sizes that blurr your observations.

All in all, a lot of work juxtaposed to the expected result, I think.

Now, if you observe a very aggressive player and realize that he obviously only pushes and calls if he has a certain amount of coverage (scared to bust) then you should adjust your pushing and calling range accordingly. By how much I don't know but I doubt that there is lots of value doing this with a formula. I would just open up pushing a lot more if I had him covered and call slightly less.