Nintendo - Game Boy / Color (Gambatte) configuration

Hello,

I wanted to emulate GameBoy - DMG games properly and I like the green color pallete.

I downloaded Gambatte and modified the launcher for GameBoy games and everything works fine.

ROM=/home/cpi/games/GBC
ROM_SO=/home/cpi/apps/emulators/gambatte_libretro.so
EXT=gb,gbc
LAUNCHER=retroarch -L
TITLE=GameBoy Roms
SO_URL=http://buildbot.libretro.com/nightly/linux/armv7-neon-hf/latest/gambatte_libretro.so.zip

On this page I found settings for GB Colorization and palettes:
http://docs.libretro.com/library/gambatte/

Internal Palette: GB - DMG - this is the closest example to what I’m looking for.

But I’m looking for help, how to set variables like:

gambatte_gb_colorization = "internal"
gambatte_gb_internal_palette = "GB - DMG"

Or even my custom one. I don’t see any specific configuration file for the new RetroArch core.

Can someone please help me with the solution?