Assuming we agree with the concept of Cultural Revolution. Does it make sense for a Revolutionary Party to start thinking about the nature of the CR early on, before taking power, or does it only makes sense to consider it once the whole country becomes revolutionary and that we can study the objective conditions on the new revolutionary society? I'm leaning towards the later, but then again, I am also under the impression that the former is possible (e.g. Black liberation movements in the US tried to do some version of CR) and that the earlier it starts being theorized, the better.
For western countries I would suggest CR first as battling reactionary elements and getting the inactive public active is crucial: you would need massive numbers to change America or Britain into a social democracy or most of the reactionary population would have to be unable to resist (if say they all die from diseases they insist are fake).
In countries that aren't quite so beaten into capitalist worship I think the key is to gain power first so imperialists can't see the signs and start acting against the CR (like Iran being coup'd because of the threat of nationalizing of oil, just going full vanguard and then doing it gives the cia and mi5 less time to plan).