How do I add custom resolution collections and overlays?

[Milkysunshine]

I'm looking to add qHD (quarter HD, which is 960x540) to the resolutions for both creating collections as well as overlays. The quality of those is superior to 480p, and I'd like to differentiate between the 2. I assume I can edit the default files, but is there a better way via a custom conf?

Thanks in advance.