You can use 6x9 negatives in these sleeves. They are designed to hold one roll of 120 film, not matter if you shoot 6x6, 6x7 or 6x9. So as long as the roll is 120, you should be able to have the entire roll fit in one sheet. The sheets are not designed to hold slides, ie positive chrome that has been mounted into a cardboard frame. But a 120 roll of slide film (ie color positive or chrome film) should be fine.

Yes, this page will fit in the Print File portfolio box.

It’s a 100 pack, of 4-strips of three frames, horizontal.

Normal binders are designed for standard paper size of 8.5x11" while the larger size increases the width by about 1 extra inch (allowing for 3 6x6/6x7 frames across- or 4 645 negative frames).

Yes¡

Yes, the Print File Archival Storage Page for Negatives, 6x7cm (120), 4-Strips of 3-Frames, Horizontal, (Oversized Binder Only) - 100 Pack will accept 10 negatives with a frame size of 6x7.

The Print File Oversized Heavy Duty 3-Ring Binder, BH # PRB would be best to use in this case. https://bhpho.to/3WQw6ze

120-9HB has seven holes with nine negatives (6X7) pockets