Running 4 screens as one with Mac Pro Late 2013

Question

Hello there, got a Mac Pro late 2013 edition driving 4 60" 1080P screens in a 2x2 configuration.  Trying to make those work as one 4k display.  Was able to get it working to allow us to display a page across all 4 displays.  But have not been able to get a video to display across all 4.  Our current  configuration has also been very finnicky and anytime we move the webpage around, it snaps the window to be full screen across the bottem two displays. 
Anyone have any idea's as to how to make this work the way we are wanting to?

Answer 1

"Fullscreen" is a garbage feature ported from IOS and the iPhone, the land of tiny screens and one-at-a-time processing -- AVOID it at all costs.
This will work as long as you stretch a Window across multiple screens, and turn OFF all hints that you want multiple, independent screens.
This describes the new ways Mavericks tries to undercut the way it used to work:
OS X: Using Multiple Displays in Mavericks