Is this possible to do via the retroarch configs or do I need to dig into each of the emulator configs?
I hooked my Pi up to an NTSC source that works fine, but I found running things in 320×240 reduces flicker quite significantly. Problem is that resolution leaves bars on the sides for most emulators, but some don’t need tweaking.
On my old modded xbox, there was a tool for each emulator that allowed you to set the overscan amounts per emulator, hoping some kind of config/tool like that exists in retroarch as well.