Yes. I'm just using display 1 (GTX260). The card is powerful enough to handle all 5 wow instances and given decent fps with full shadows on main at 1680x1050. The workaround is too fiddly for me.

As for horizontal span, it is not available in Nvidia's control panel for me (Vista 64), I assume because a) it was removed or b) my monitors have different native resolutions (i.e. horizontal span would not work for me anyway - link ).