[Nix-dev] Configuring dual head

[Tony White]

Does anyone have dual head for xorg working from configuration.nix and
can provide or point me towards a working example please?
If I use simply :

      isClone = true;

In configuration.nix the xserver fails to start, Even though
nixos-rebuild switch completes cleanly.

      isClone = false; allows the xserver to start.

Any suggestions would be helpful, I've got an xorg.config that works
with dual head that I can use to create the configuration but there
are so many options, I'm a little lost on how much of the data needs
to be added to configuration.nix

Thanks,

Tony