2-way SLI w/ GTX 1080 on Ubuntu 14.04LTS

Have had a lot of difficulty with getting 2-way SLI working on two GTX 1080 running on Ubuntu 14.04LTS.

When 2 graphics cards were recognized by the system. In Nvidia Xscreen settings, you could only set 1 card as “screen 0” and the other was forced to “screen 1” which was just a black screen with an “x” moving around it.