Was the choice of 6 (and 25 for searching) based on research?
Stephen Keable

From a HCI perspective:
<6: Tolerable to the persons short term memory and searching
>6: Involves more clicks and obscures the overview.

If the >6 options where displayed similarly as the <6 it would also be harder to search through at which point categorization and contextual search would ease this pain.

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