To update the geometry of a surface in all scenes at once, just select all scenes, press the "Edit" button in the cue area and adjust the quad geometry (or press the "Output Geometry" button in the quad properties - this button appears only in Cue Edit mode)
In Cue Edit mode, properties of surfaces/medias that are included in the selected cues appear with an underline, red if the value in all selected cues matches the current parameter value, orange if the value in the cue is different or if this parameter is not stored in ALL selected cues. Pressing a parameter (slider, combobox, checkbox etc) will update (iof orange)/add (if not underlined)/remove(if red) this parameter in all selected cues. So if you want to update a surface output geometry in all scenes at once, just do as described: select all scenes/cues to update, select you quad, go to edit mode and press the "Output Geomtry" button.
This is a bit complicated but once you got it it's very powerful !