Switchover will follow your model calendar. Lowest a model calendar can go is weeks.
To get switchover to daily, you'll most likely need to create a module to hold the current date. That can be automated, by the way using Anaplan Connect. Once you have the current date you can use formulas to determine the switchover. To be honest, this is the method I use because I don't want to have a casual Anaplan user have to become a workspace adminsitrator to change the switchover. Hope that helps!
Two approaches, both use DISCO, neither use switchover:
Use the native versions in one module (Module A). One for Actuals, one for Forecast. Add another module (Module B) that contains the current date. In Module A you'll add a line item that has this format: IF PERIOD(START()) >= Module B.Current Date THEN Sales[SELECT: versions.forecast] ELSE Sales[SELECT: version.actual]
Same as 1, except you'll denormalize the forecasts and actuals and create a separate line item for each instead of using the native versions. Your formula will look something like this: IF PERIOD(START()) >= Module B.Current Date THEN Sales Forecast ELSE Sales Actual
One nice thing about option 1 is that you can make the actuals read only and forecast editable using the feature to apply formula to a version.