The Interactive Schedule settings used by your local Archicad are saved as .iss files in ~/Library/Application Support/Graphisoft/IS Settings.
('~' means home, the house-looking folder named after you.)
But you don't actually use them there, so that's just FYI.
The standard IS settings, for the techniques I will describe here as they become available/I have time, are at 3 Resources (Onion)/Interactive Schedule. You use the IS interface to get these into your projects. Either: Calculate -> Interactive Schedule -> Settings...; or Calculate -> Interactive Schedule -> Preview..., and then the 'Import Settings From...' button. I prefer the second method; you can get from Preview to Settings but not the other way around, and I don't know why you'd fiddle with IS settings and then not want to see the schedule. (Maybe I'll just take that Settings menu item off. Let's move on.)
You can import multiple .iss's at once.
While it is possible to Change the Settings Folder, I would like explicitly forbid that you do so. Especially, don't use the 3 Resources/Interactive Schedule folder directly. If you do so and then make changes, you are Messing Things Up™. By keeping all the schedules settings local, you can mess them up all you want, as you need to, and you can always re-import the standard ones. That is, feel free to experiment.
I'll point out in passing that IS settings are handled very similarly to Work Environment schemes, and differently from attributes and library parts, and differently from conventional list schemes, which aren't library parts but are in the loaded libraries. It's really insanely complex. Maybe someday there will be a unified external asset manager for all this stuff, and the view sets too. And the display options.