[HTTPS-Everywhere] Design Question for companies with multiple websites

[Numismatika]

Hello list,
i was thinking about creating rules that cover the zam network.
One rule for each subsite they run was the first idea, since some big
companies like google also have multiple rules already in HTTPS-Everywhere.
Then i thought, some of the content-cdn is shared, so one rule for all
the sites would also be possible.
Is that something where one rolls the dice or is it a question of some
other factors, like size , amount of involved and shared sub-domains?

Regards,
Numismatika