I believe I understand exactly what you mean by the vertical play. That is one of the two spots on the camera where there can be wear. We have had duplicate parts made, but we need to keep them for ourselves as we have five or six Kodak Master View cameras. (One cannot have too many and most of those participating in this thread got their KMVs after seeing ours in a workshop.)
But if after you set up, lock everything and insert the holder, there is no movement, don't worry about it as there is no need to do anything.
Michael A. Smith