the only things which I found out are basically command line arguments for ll3.exe
-singlemonitor: disables second monitor
-windowmode: disables fullscreen mode
-sw X: set screen width (where X is the pixel width)
-sh X: set screen height (where X is the pixel height)
-centralmode: forces the game to run to central mode (gacha touch screen application) instead of satellite mode (the default mode with two screens)
-highquality: improves the game quality (expect your GPU usage go stonk)
NOTE: on ll3test.exe if you run with the argument -centralmode it won't go on test mode and it loads normally