Adding a Graphics Card to an Amiga 500

Always after ways to push the trusty Amiga 500 to new limits, I discovered a post on the German A1k.org website about someone who had fitted a graphics card to his A500. This was a feat I felt I should replicate. I'm almost, but not quite, there. However, there were lots of hoops which needed jumping through first...It's Amiga weekend, apparently! This story is a bit more hardware-focuseed, obviously.