First of all, I appreciate the work on the scanline overlays, thanks! My suggestion was to leave the RPi overlays as they are since they work well and are easy to find.
The post above is a good summary. After some thought I understand why using ‘overlay0_full_screen = false’ could be useful, it make the use of overlays independent of the users screen resolution. However, in my opinion it makes the selection rather unintuitive with so many options available.
If regular 720p or 1080p are assumed then using ‘overlay0_full_screen = true’ would reduce the number required to just the three basic ones 720p 3x, 1080p 4x and 1080p 5x (for each pattern).
Maybe each pattern could have a name for easier identification, for example option 1 could be ‘sharp’. Of course, it’s up to you.