First question are you trying to setup a Nvidia Surround rig? If yes you should know that all three monitors in a Surround setup need to have the same specs so running two at 1080p and the third at 1920x1200 will not work correctly. You would need all three at 1080p or all three at 1920x1200.
If however you are running them as Extended desktop then there should be no problem. Plus if you are gaming on a single monitor you should be OK even with a single GTX 770. With the second configuration I do not think you would even need SLI because you are not going to max the bandwidth of that card on one monitor in games.