The back for my 5x7 Korona is an exact fit except for the width of the perimeter baffle, so I know a 5x7 back would fit. My interest is to make it a 4x5, not only based on cost but also availability of film options, but its just as easy to build two backs (4x5 and 5x7) as to build one once you set your router bits at the right height! But you are right, it is a half-plate English style camera, taking a #2 panning tripod. I am also having to make a tripod adapter for it.