Finally replaced my secondary 19 Inch Display with a second 22 Inch and now running 1680×1050 in twin view.
In case you have problem setting up Twin view with 3d acceleration i highly recommend installing EnvyNG which will download drivers and setup most of the configuration for you.
The final step is to tweak your configuration using nvidia-settings.
In case you have problems with full screen applications (such as games) running centered on both screens you can bind the application to a screen using the meta mode function in your xorg.conf
Option "metamodes" "CRT-0: nvidia-auto-select +0+0, CRT-1: nvidia-auto-select +1680+0; CRT-0: NULL, CRT-1: nvidia-auto-select +0+0"
Adding a NULL value to your option will make sure the application only launches on one screen.