problem/doubt with 3 button arcade games config

[yesansa]

Hi guys.
I have a problem/doubt with games with only 3 buttons like Metal slug.
I have the latest retropie image downloaded last week from the website which version is 4.7.1.
This version mainly uses FBNeo for arcade games/NeoGeo games.
I have set up my joysticks and 6 buttons as the SNES gamepad

Y X L
B A R

Which is fine for 2 button games => Attack and jump or special attack in the bottom row
4 button games as Fatal Fury => Puch bottom row and kick top row
6 button games as Street Fighter => Kicks bottom row and Punches top row.
So far so good.

But with 3 button games as Metal slug as I said the grenade is mapped to Y when it should be in R to be all the buttons in the bottom row.
I know I can make a .cfg with the configs per rom putting it in the same folder as the rom or in /opt/retropie/configs/Fba (0.73) i think is the folder for roms configuration for FBNeo.
But to do this I should have a button game list for arcade/NeoGeo and create a .cfg per every rom.
Is there an easy walkaround to do this or even a list with the 3 button games to do it myself?

Thank you and sorry for the long post

[yesansa]

Hi Guys.
This might be more complicated than expected. I have read something about autoconfig, but I think it doesn´t fit this case.
So, right now I am trying Plan B which is made a .cfg file for each 3 button game to override retroarch.cfg and have a 3 button game config.
Now the hard part of this is to find a list with all the 3 button games, or at least to able to filter down my roms to know which ones are "3 button game"
but so far I haven´t been able to find a list or find a method to filter down my romset.
Just the museum arcade have an advanced search with 3 button layout option, but it only show me 150 results .
Any idea?