Okay, I don't really think that modifying the graphic settings using this method is a good idea, because I believe the GameOptions.ini is different on each operating system, and between 64 | 32 bit OS.
Your settings as you provided:
Mine is way different by default actually:
I believe using the in-game settings to modify the graphics would be way better and non-risky to do rather than doing it manually!
Thanks for share anyway.