With regards to IRC - in my experience, once you get passed the authentication problems and often session timeout/kick out, you see the chat room with 300 people but no one chatting or answering. Kind of reduces the worth of the chatroom this way in my opinion. Although, I am in Australia so the timezone I am in could be a contributor.
I'm also in Australia, but my IRC experience has been different from yours. I find that the individual, project-specific OpenStack IRC channels are a great resource, often attended by really helpful experts. 'openstack-ansible' 'openstack-ironic' 'openstack-qa' etc.
Also, I keep a teeny tiny VM running in Google's cloud (AU 20 cents a month) to run quassel core so I have a 24/7 IRC connection to channels I watch so that people can reply to me while I'm asleep and I can catch up the next day.
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MC