I have just recently got a 23CIIXL enlarger and it was set up for 35mm with 50mm El Nikkor lens and neg carrier. I am trying to get set up for 6x4.5 for my Bronica ETRSi and I am finding 6x6 negative carriers that I can use and looking for a lens. I have found lens boards that have different mounting holes and wonder if 39mm might be the standard one. Freestyle has lens boards with 39mm hole and also some on ebay. I have seen several lenses on ebay and just wondering which ones are good and if there are any to stay away from. There are some lenses that are 75mm and some 80mm and I guess that range is OK for medium format.