Two identical monitors are essential for doing this - sounds obvious, but you'd be surprised the amount of people use the TFT monitor provided with Catalyst and A.N.Other ACME monitor... This won't do, really.

You know then that you are sending a perfect data signal to the projector or video wall processor, and you can show your projectionist or screen tech what you are after from them.

Christian - what is you inverting problem???

Hugh