Re: 4 monitors, two cards, twinview, center on monitor
No compiz makes the twinview setup usable, without it, clicking maximize on a window maximizes it to the fill twinview screen size.
I actually want the twinview behaviour in general which allows me to move windows between two monitors etc. X11 is not capable of moving windows between screens.
The thing I am missing is that at the moment Gnome thinks the center of the twinview screen is between the two monitors. When I still had just two monitors and one card I got the desired behaviour where anything that should be centered appears centered on the monitor on which I am working at the moment.