The 13-1/4" wide Cecilian rolls were not only wider than most other
65-note rolls, but the scale was such that the spacing between holes in
the tracker bar was least in the middle and increased outwardly toward
both edges.  Also, the holes themselves were wider the farther they
were from the center.

I would presume that it was to compensate for expansion of the paper
roll.  There is some pretty good music on some of those Cecilian rolls.

Hal Davis