If you're opening listers when Opus starts, create a Layout with the lister where you want it and then set Opus to open that layout on startup:
[Saving lister layout)
I find it better to start Opus with Windows and not open any listers on startup, then open and close listers as and when I need them, usually by double-clicking the desktop or the tray icon. Since Opus is already running it's quick to open new listers.
If you're opening listers by double-clicking the desktop then you can set them to open where the mouse pointer is, or to open a saved layout. The same is true for the tray icon.