Wall, chaps - two news. The good one and the bad one.
The good one is - nothing blew up when I've connected all the bits and pieces together.
The bad one is - it doesn't work. The computer boots up and nothing - only a blank screen on the monitor. It doesn't matter which DVI port I plug it in - it stays black.

Moreover, after a while the system fans start going crazy (the 'wind tunnel mode') which is quite strange. Nevertheless - the X1950 Pro AGP version doesn't work with current MorphOS. At least here.