Hi Dan,
I have looked in the settings window, and the only black box that I can see is the one on the top right:
I can adjust the size of the image, but the biggest it will go is about 75cm from 2 meters away.
I have also tried adjuting the size of the image in the frame, that makes the image larger too, but then it all goes off-frame (the max frame size right now is about 10-15 degrees. So I am stuck really.
I want to open up the projector, but it is still under warranty, and it might have to go back to Germany yet.