Hi,
Just an FYI that I've just finished up Michael Holloway's work on getting Event Stream Config to support per wiki and/or group overrides https://phabricator.wikimedia.org/T277193 in wgEventStreams.
If you need to override settings for EventLogging like sample rate, it is now possible to do so. Documentation here https://wikitech.wikimedia.org/wiki/Event_Platform/Instrumentation_How_To#Overriding_event_stream_config_settings .
The main change to make this work was to start keying stream configs by stream name. There is no longer a 'stream' setting you have to add to the config.
Enjoy!
-Andrew Otto SRE, Data Engineering Wikimedia Foundation