I used to prefer glass inserts (anti-newton?) for my Durst. I used to have a Durst at home so I took my neg carrier into college as it was better than the scabby ones they had. The only problem I had was dust but the trade off was the negs were perfectly flat and could print full frame. Pretty sure the carrier I had used to have movable blades on it as well. I also acquired a set of 35mm inserts which I filed down - the edge round the neg gave a nice frame to the finished print (specially when printing cross processed slides onto normal paper)