So one thing you may have missed in that article was in override the initialize method.
and a Boolean value to determine whether the Basic Settings are global (false) or per site (true).
There is also another article I think handles this a little better.
In this case the setting is in SystemManager.RegisterBasicSettings("GoogleMaps", "GoogleMaps", "CustomResources", false);
That final false is the flag to be set for multisite. Let me know if this helps and if not we can get back and I will see what I can get set up on my end.
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