Is our triathlete learning?

A friend bought me a copy of Joe Friel's The Triathlete's Training Bible.

Funny how I finally found time to start reading it when the TV was not available. Have read about 70 pages so far. Pretty interesting. Notable items:

1) the split in % of fat/carb burning at different intensities. Looks very useful for planning a long workout where you will exhaust your carbs at some point.

2) the 80/20 rule for gain from working out shows that you get the most bang for your buck working out 3-5 times a week. I like to see that since going over 5 times a week would be difficult for me to schedule.

3) your body produces HGH when you a) work it hard and b) sleep. There have been other benefits to splitting long workouts into 2 per day that I've heard of but that is a new one.

4) One of the keys to being able to use the book for successful training is being able to feel your effort level and grade it on a scale of 20 values. This worries me that I may not be able to make training plans based on this because I think it is tough already telling which of the 5 more traditional HR zones I might be in. 5-8 levels of feel is about the most I think I can distinguish. Maybe there are only a few critical thresholds and being able to tell them apart will do.