There are two things you can try. You can try resizing the font of the tab numbers (the smallest you can make them is 4, but you have to type it in the box as it's not readily selectable). Or, you can try to turn the tab numbers off altogether so you can see the fold lines. In either case, it's always recommended and helpful to have the file open on a computer in front of you as you work on the piece, so you can reference any uncertainties you have.