6-monitor, 2 GPU display in RHEL7

I am not a Sysadmin, but I probably know enough to be dangerous.

6 Monitors, 2 nvidia Quadro 4000 GPUs, currently I have 4 monitors on one, 2 on the other.

I am having great difficulty getting the display to work the way I would like. My first hope was to have all 6 monitors working as one large screen, but I would, at this point, be happy to have one 4-monitor display with an additional 2-monitor display next to it.

I’ve tried the manual GUI for rearranging the monitors (I “enable” the two monitors on the 2nd GPU as “Xscreen1”). After dragging and arranging them as they should be, I save an Xorg file from the software. When I stop and re-start X, it encounters a problem, and freezes. I’ve tried editing and playing around with the /etc/X11/xorg.conf file. It would be especially helpful if there was an example out there that I could just use as a template.

If anybody could provide such a template, or suggest something other (xrandr?) as a better way to go, I would greatly appreciate it.

You could use this doc for configuring multiple monitors:
http://us.download.nvidia.com/XFree86/Linux-x86/367.44/README/configtwinview.html
You could also generate a bug report after X crashes/freezes and put it in this thread as explained here:
https://devtalk.nvidia.com/default/topic/522835/linux/if-you-have-a-problem-please-read-this-first/