A wall chart has one job: give a room the same picture at the same time. When we cram channel, region, and plan type onto a single poster, people stand at different corners and argue past each other.
For flagship maps we print one primary matrix large. Supporting cuts live in the slide pack or as smaller side sheets. The primary matrix usually holds the full population for the agreed entry event. Segments appear only when the decision under discussion is explicitly about that cut — for example, comparing annual versus monthly plans before a pricing change.
Typography matters more than colour drama. Axis labels must be readable from two metres away. Callouts should be few enough to count on one hand. If you need more than five annotations, you probably need two meetings or two posters.
If your next review room has a blank wall, measure it before you brief us. Physical size changes how many columns we can honour without shrinking type into decoration.