Questions about video settings, integer scales and shaders

[Lendário]

I'm very new to emulation and i'm totally lost on some things. So i think you folks can help me. I'm looking for the "correct" video settings, if there is such thing, for SNES, Mega Drive, PC Engine and PSX.

For 2D systems i THINK i have it figured out.

Regular 1080p TV, RPI 3.
Recalbox/Retroarch resolution is set to 720p.
Game ratio is Auto/Core Provided/4:3
Smooth Games is off
Integer Scale is off
Crop Overscan is on
Pixellate shader, filter is nearest and scale "Don't Care"

I have the resolution (Recalbox's not the TV's) at 720p because i read at more then one place that it's better then 1080p. Why exactly is that?

For Aspect Ratio i understood that basically had to choose between 4:3/TV look or 8:7 (1:1 PAR)/Correct Geometry. I picked 4:3

The pixellate shader is because, if i understood it right, it corrects all the problems that not using Integer Scale and bilinear filtering causes.

To finish with 2D games, i noticed one weird thing. In Skyblazer i get full vertical scaling, but in Final Fantasy VI, it's only full vertical scaling on the world map, i get very small black bars otherwise. Is this a game thing or something about the settings?

About PSX's 3D games, would the exact same settings work? I'm guessing the Pixellate shader would not correct the things it does in that case.

Sorry for the long post, but i'm really lost on this stuff.

[Substring]

@lendário Hum ... I'm definitely not in the shader sutff.

What I can say is that, depending on the shaders, it can be CPU intensive. That's why we recommend 720p : that's just for a performance issue.

Regarding the ratio ... That's again a different story. This all depends if you want plain square pixels, or if you want to emulate the 4:3 stretching done by TV. There is much to argue about that ... Once again, not the kind of thing that matters when I play.

Integer scale is something interesting but "looks best" on 1280x1024 as it's the resolution that is the closest to integer multiples of original resolutions without having too much black borders. When you don't use integer scale, you need bilinear filtering to avoid some graphical issues.

I'm not of much help here, i don't have the same goal when playing