Hello Mercury,
I follow the correlations as well. I have a quantitative reason for not following the CSI300 ( correlation too low) and the EUSTX50 (too similar to the Dax). I even have a reason to favour daily, hourly and 15 minute candles.
This is what the correlations of the SPX500, JPN225 and GER30 look like over the last 24 hours of trading.