What do these settings mean?

fast or extra are for the light compile time, with extra it took 1 hour to compile light for wine and theres not any difference just waste of time.
no model shadows cause models to not cast any shadows.

the rest im not sure i never tried them :l but i dont think its a good idea to mess with them

You can use "Extra" for your final compile as it does enhance the quality of your lighting. But as jj said, there's no point in using that as long as your map is WIP.