I am finally setting up an Omega E3 I picked up many years ago. I have a question about the 5x7 negative carrier, and that is: how does it go together? When I got it there was a piece of glass taped to the top half, and nothing on the bottom. There are clips on the top, and springs and clips on the bottom. See attached pictures. I assume the glass goes on the springs, but the piece I have doesn't fit (but it's probably not original). Then I assume the negative sits on the glass without a top glass, since the clips on the top piece don't look like they could hold a piece of glass. Does this sound right? What is held by the top clips?