On-import Backup Subdirectory Supression?

On import when enabling "Backup To", is there a way to make C1 not create/use a (date-based) subdirectory?

Or, perhaps, a way to make it use an underscore rather than a space as a delimiter? E.g., "2018-12-26 12.30.53" => "2018-12-26_12.30.53".