@mitu Thank you for your response and help.
Setting the Retroarch system settings for video aspect ratio within the EmulationStation Retropie configuration menu, worked perfectly and saves the settings for all cores.
Now when I open a game, in any core, I am able to "Save Core Preset" as well as "Save Game Preset" for an individual game within a core that already has a shader saved for that core. Brilliant!
Everything seems to be working now.
Just to better explain what I am doing with the system. I have a cocktail table that is used for 2-player alternating and simultaneous games.
I use the Arcade folder and lr-mame2003 core for Cocktail specific MAME ROMs that have the Cocktail option in the ROM “Dip Switches” for 2-player alternating games. Primary player has a turn and then the screen flips and the secondary player has a turn.
I then use the FBA folder and lr-fbneo for other MAME ROMs for 2-player simultaneous game play using a “Split Screen” Shader. The split screen shader allows both players to have their own screen (within the single monitor) for simultaneous play. I have three different “Split Screen” Shader files that I have to use because not all ROMs setup the same. I save one “Split Screen” Shader to the core that’s takes care of the bulk of the games and then I have to use one of the other two shaders to save for individual games that seem to setup differently than the bulk of them.
I save a custom shader to the core as well as individual games within the same core…
Cheers