How do you use your Durst with only one sheet of glass? In other words, how do you hold the negative flat?
The only way I can see that working on my Durst L1000 would be to use the top 1/2 of the metal film holder and replace the bottom 1/2 with the glass.
I use a glass on top of the negative to hold it flat and protect from the heat.
I have a diffusion light head...Ilford 500 system :-)