Layouts can use Assure's built-in "interpret" function, which will take a literal text value and process it as a variable during execution.
For example, within the More -> Advanced Path/URL settings within a Layout, you can access a runtime field named "filepath" with the following code:
@interpret ( 'runtime.filepath' )
This removes the need to set the override on each control that uses this layout. When the control is run, if it has a runtime field named filepath, the value of that runtime field will be sent to the Layout as its Path/URL.