I picked up a 4 x 4 Kodak Gel # 58, not realizing that it was so thin and didn't come in a frame or anything. How can I use this type of filter with the Lee system? I looked around and couldn't find any filter frames or anything, I'm either missing it or they don't exist. I have a 90 mm Nikkor 4.5 which has a large filter thread, so the little snap on frame doesn't look usable-anyway, how would one then use a lens shade? Any tricks or suggestions would be helpful.