You’re welcome!, glad you are enjoying the shader package
So by default it should be set to 2 which is “crop any”, and 1 is “crop only black”.
The thing with the cropping is that you must set some cropping values to see any effect, for example you could set crop left to 10 to get a 10% crop off the left side. If you had it set to “crop any” it would always take off that 10%. If you set “only crop black” then it would crop only black, and only up to the 10% you chose.
The Mega Bezel logo (or whatever image you decide to use) is “placed inside the signal” of you will, so it will be processed as the rest of the signal is, E.G. Scanlines etc. So it is displayed with the same resolution as if it was coming from the game. If you play a game with a higher resolution, like dreamcast it would be much more detailed. I imagine it might look rough on an atari 2600 game
So that one specifically is part of the Mega Bezel package, you can find a preset in the variations folder, it should be called Night something. There have been wonderful graphics and preset packages done by amazing artists in the community, you can find them at the end of the first post in this thread.
This is still on my TODO list because it requires a new feature to be added to retroarch. I got partway through implementing this and paused on it because it was going need a fair bit more work to complete.
So the potato presets are really focused on being able to run on potatoes, and therefore have most things stripped out of them that are expensive, and the reflection is one of the performance eating features that has been removed. Right now the Potato presets are really like a easier alternative to using traditional Retroarch overlays to apply graphics.