A useful multi-monitor setup gives each display a role, then groups windows by project across those roles. The monitor is a location; the project is the reason the window is there. Keep both clues consistent.
Assign display roles before app positions
Choose a primary display for the action that changes the work: editing, coding, or presenting. Use the secondary display for references, logs, or previews. Put communication on a third display only if it must remain visible.
This role-based setup survives app changes better than rules such as “browser always left,” because a browser can be either the working surface or a reference.
Decide how Spaces behave per display
The “Displays have separate Spaces” setting gives each display its own Spaces model and makes the Dock available on all displays. It is also required for Stage Manager and for Split View on other displays. Test switching behavior before building a large desktop map.
When the setting changes, macOS may require logout and the navigation model changes. Record the intended configuration instead of treating it as a minor visual preference.
Keep a recovery path
Create a simple project map: action window, primary reference, optional live output. Give similar windows distinct titles. After disconnecting and reconnecting a display, use Mission Control to confirm that all required windows remain accessible.
Wallo can group selected current windows across apps and displays under one goal, but it does not enforce monitor placement. A layout tool can manage geometry; a project group can preserve the outcome label. Use both only when both problems recur.