Metamode seems to be ignored -bezel correction [Partly solved]

Gave it a try but no joy so far. I was under the impression that twinview was only for dual monitors.
But I tried it in the section you suggested and also in the 'Device section as the documentation suggested in Appendix G
Also tried moving my metamodes to the Devices section as per the docs.

In everything I’ve tried there is always the line in the log
(**) NVIDIA(0): Option “MetaModes” “DP-2: 1920x1080_75 +1920+0, DP-0: 1920x1080_75 +0+0, DP-4: 1920x1080_75 +3840+0”

Which does not match mine
Option “metamodes” “DP-0: 1920x1080_75 +0+0, DP-2: 1920x1080_75 +1962+0, DP-4: 1920x1080_75 +3924+0”

Out of interest I commented out my MetaModes line.
(**) NVIDIA(0): Option “MetaModes” "DP-2: 1920x1080_75 +1920+0, DP-0: 1920x1080_75 +0+0, DP-4:
still appears in the log.
But it’s clearly coming from somewhere other than the config file ?
I briefly changed the identifier. To make sure there was no other copy of this conf file lurking somewhere. But as expected X failed to start.

So it seems to me no matter what I set as my MetaMode the driver just ignores it and makes it’s own mind up ?
Half giving up as it’s not a biggie for me. But if anyone knows the answer please enlighten me.
Going to have a look at the command line and see if the driver will listen to my wishes there :)

Edited to add:
Next thought was to try xrandr. That doesn’t seem to work when xinerama is enabled ? (does work when it isn’t)
$ xrandr --verbose
RandR extension missing

The odd thing is I can change the absolute positions in the nvidia-settings GUI. Press apply and it works. I have my bezel correction. But then click ‘Save to Xconfig file’, Fire up an xserver with that .conf and it overrides the custom metamode again (palm hit face)