One TH2G may give you more than 3x 800x600 on an X1900XT. I've managed 3x 1024x768 (3072x768) as well as the 1st output (total 4 x 1024x768).

Using 2 x TH2G on an X1900XT I've only managed 6x 800x600 (2x 2400x600)

The TH2G is seen by the OS (and catalyst) as one big widescreen display connected to the output of the graphics card. Catalyst handles this by positioning mix windows to co-inside with each of the '1024x768' sections (assuming 3072x768)

Depending upon the mode selected for each mix window, it is indeed possible to keystone each output of the TH2G and/or edge blend.

Most people find TH2G & DH2G quite easy to configure. However - this is not always the case... ALWAYS test before you get onsite!!!!!!!

Let me know if you'd like to try out any configuration before making a purchase

Simon