Here are all the MI Valueline screens returns over this time period.

Sorry ... am I correct that those are the screen returns during the beginning and ending periods you defined starting with 6% CPI values?

I don't think the desire to avoid a bear is dead; I certainly have that desire, having started investing soon before the great recession.
There was that, other 30% downturns, and lastly the period of underperformance starting in 2018 and capped by the pandemic.
In hindsight, all times that one would rather avoid.

During those bears, I was struck a couple times by how the absolute values of NH-NL got to be an extreme negative number.
Like, -700 or -1000 or something, don't recall. So one strategy for improving your strategy's returns would be:
- exit the market near a top (various indicators are said to be able to give a reasonable signal)
- enter back in during days of extreme negative breadth (rather like mungofitch's major bottom detectors)

Something like this would not guarantee that you picked either the top or the bottom. There may be multiple bad breadth days before a bottom is set.
And you never know if the bottoming process takes months or years. However, if you could do this in real life, it should improve your performance.

Mark