For the CAMARA vs ENLARGER conceptualization, in your mind just put the bellows toward the light sensitive material. Now the enlarger and camera are essentially identical in terms of the physics and optical equations.
In fact, in the Durst literature what you might call the 'enlarger head' is called a 'camera.'
Thanks to everybody for your precious advice! I have enlarged some super 8mm film to 140x200cm and posted my results on (there was a url link here which no longer exists)
gm