I've read and re-read that entire chapter. The closest it comes to talking about number of intervals and length of intervals is "duration, high/medium/low".

I have 3rd Edition of that book. Does the most current (4th Edition) say something different in that chapter?

There has to be some sort of starting-point for determining number and duration of intervals, am I right? From there you progress them dependent entirely on how you respond to them, right? What's the procedure, here?