w/o string i can't even boot normally into my system.
My screen was split a half, awful colors, and other cool stuff when optimus shows its true nature."
That's not optimus related, it's because you have a Full HD Screen. Boot without the string and see if you can enter Dashboard/LaunchPad smoothly, also see if the menu bar option is available then. It's possible the string i made is not compatible with your system.
It is possible to boot w/o string and get normal colors and uncut full-hd screen only when all the video drivers are removed.
Otherwise my screen is corrupted, and yes, dashboard is still glitchy in both cases.
So your string was a cure to make OS loaded properly with appropriate kexts.
Maybe i should run some hardware reporting tool to see specific issues related only to that particular dell xps l502x revision (and make my own string afterwards)?