Just an update on this: apparently you can change to NTSC and the Sony palette within RetroArch running this core. You just have to make sure you load a C64 disk image first then the Options menu opens up with the ability to select and save your NTSC/Sony palette configuration. This is promising. And I just want to thank Pete again for giving me the original info that changing to NTSC with the Sony palette makes the games look MUCH better than with PAL. Colors are just so much more vivid and games run much smoother with that extra 10 FPS that 60 Hz affords as opposed to the 50 Hz standard of PAL. Unfortunately, you do lose a lot of compatibility with euro games that were only designed to run in PAL but at least it looks like I remember my old C64 looking like on my old CRT television in the late 1980s/early 90s. Now if the author of the VICE libretto can only update it and implement a way to swap disks without the terrible tedium of creating "flipfiles" this would be the definitive way to play emulated C64 games and software. Perhaps in the next update.