I am planning to upgrade my Beseler printmaker 35 to be able to print medium format negatives, specifically 6 x 6 negs. I know there is a upgrading kit commercially available from Beseler. After I found the condenser glass in EBAY and called the store to be sure it was the one that would fit my Head, the guy told me that this would'nt be a good idea because the Beseler 35's dimensions, even after upgrading the lens to 75mm and applying the right condenser glass would cause vignetting problems. He recomended and offered to look for an available, used, medium format head that would fit my chassis. My questions are: 1. The glass that fits the beseler 35 is the same as the one for the beseler 67 (which is made for both 35 and mf.). If the gentleman that helped me is correct, what is the dimensinal difference between the two products that causes vignetting problems in the beseler 35? Is the bellows dimensional difference is what would cause the vignetting? Is it some difference in the dimension of the box or light quality? 2. Is it relatively easy to find/install a different head unto my beseler chassis? 3. What is the difference in quality of print if I use a 75mm lens as opposed to a 80mm for med. format? 4. The upgrade kit the beseler sells has two exact condenser glasses to be placed in the head. I currently use only one for 35mm (that is the way Adorama sold it to me, new). Will there be problems with using only one for medium format if I decide to go with my own printmaker 35 head? Thank you all for your help!!