Hi. I'm not sure how much help I can be in this, but I'll give a try. I run two different cards with one monitor each, and setting them up was interesting. I had to do quite a bit of reading and googling to get things the way I wanted, so I should at least be able to point out some pertinent docs.
Have you got the nvidia driver running exclusively (ie. making sure that the nouveau driver doesn't load at all)? I found this to be extremely important as a first step to getting things started on the right foot. I am running debian unstable so at least we are running similar releases.
As a starter, I will list a few docs I found helpful:
The Arch, Gentoo, and Debian documents I used because all three have information important to any linux/nvidia install. The Suse and Fedora links I included in case you decide to try one of those distros.
There are other guides and howto's out there, and for other distro's, but the first three were the ones that got me on the right track. I'm not telling you to RTFM. Just if you want to get started, that I think these are good starting points for these distros. In any case, I'd be glad to help.
Also, let me add the official doc from Nvidia:
If all this is old hat to you, I apologize for my long wind. If this is the case, and you have tried making adjustments via the gui - nvidia-setting control panel, direct edit of xorg.conf, and/or use of xrandr, perhaps another option is to consider different window managers.