6x9

I’m looking for an archive system for my fathers old negatives. They are a mix of 6x6 and 6x9 negatives that have been cut into individual images (i.e. they are no longer in strips). Can anyone recommend a system that will work and not involve me pushing multiple images into a multi-image slot...

I have a GORGEOUS Ensign 6x9/6x6 camera that is... Quite old. It works, even the shutter timing sounds about right down to 1/25th second (top speed a whopping 1/150th!) and is fitted with a folding 105mm f4.5 lens. Sadly, the 6x6 mask has long since disappeared (unless I'm missing a key...