I got curious about the relationships between the various targets, so I have been playing around a bit with those. FWIW, I only use the last 350 or so eras, and rather than using those complicated names I just use numbers 1 to 21.
I thought this plot might be of interest; it’s the correlation between the primary target and the whole set:
1 and 2 really aren’t visible (they’re just ones after all), but what was curious was the somewhat periodic nature of the correlation between the first target and 60 day targets, all in the lower group.
Interesting as well is the best correlation, aside from the 2 perfect ones, occurs for Target 20, which is shown in light blue. Target 20 is a 7 bin target.