They cover a number of topics. Results are all back-tested and presented for the reader to look at in detail.
1. Income harvesting strategies. The best ones convert equities to fixed income assets when total equity value has crossed a threshold (20% above starting value). McClung calls this 'prime harvesting'. Simple rebalancing works ok, but you can do better.
2. Variable withdrawal strategies. They consider several different withdrawal strategies. The best one to use depends on your retirement parameters (primarily life expectancy).
This takes you up to chapter 4. I haven't studied the other 7 chapters yet. The book considers global diversification and asset mix in detail.
The really really TLDR is that the 4% SWR isn't a problem.
1 - So say you have $100k in XAW.TO or whatever, it grows (stripping inflation) to $120k, then you sell $20k and put that $20k into bonds?
I was thinking of that myself a while back - as in, if you have a portfolio which is above the amount you need for 4% SWR, do you take a different risk profile with the amount above the 4%?
So really after this crazy run up over the last little while, you should sell (high, no less).