On conventional 88 card print sheets, there are 8 rows of cards printed 3x each across the full 264 card sheet. One slit (half-sheet) should have two checklists of series 2 and one of the series 3, while the second slit would have one of checklist 2 and two of series 3. Same pattern would repeat in the 3rd print run, etc. Here's an image of the two half-slits from 1964 & 1965 (series 3 shown, but same point) to illustrate.
1964_series_3_sheet_A.jpg
1964_series_3_sheet_B.jpg
1965_series_3.jpg