Warning do, use is on your own risk, if you do not know what or set to heavy of your system i could be doing damage to your system parts or monitor.
In this UserCfg.opt you see a lot of sections with different meaning.
Best way of reading it i find take it section by section and ask yourself
For example video the top section refering to how your graphic settings are handled
on global scale as like in your graphics card control panel and how to behave ingame.
The open sections with no description is easy
Enabled = 1 or 0 // On is 1 or Off = 0
Quality= 0 up to 3 // where 3 is highest
Hoping to profide you of some sort of an answer, concearning UserCfg.opt.