Just a quick input.
Dont play games using 2 screens unless they are designed to, or the game is (Total Annihilation im looking at you)
The central point of the screen will be the divide, and it will be a horrible gaming experience. Go for 1 or 3 monitors for gaming.
If you are wondering if your 770 can run Skyrim on 1 with maxed settings and HD mods while running other things on the other monitor, yes that will be plenty, my 670 can do that
Hope that helps.
RE inzone and the vram.
Running a fully HD modded skyrim with water and a few other mods I use over 2GB of Vram, and that is on only 1 monitor at 1080 with the other running films or a web browser. So you need to make sure the 770 that you buy has 4Gb of vram.