Ref. the article by Wayne Stahnke in 170603 MMDigest and the article
by Paul Rumph in 170531 MMDigest.  At the end of the Paul's article
is a link to an image of Artrio-Angelus roll 7512:
http://www.mmdigest.com/Attachments/17/05/31/170531_211422_AA7512b.png 

I have added dimensions to that image to show that the lowest four
channels of roll 7512 are displaced to the left 0.0133 inch relative to
the 9-hole-per-inch "uniform" grid.  Also, the right Theme hole (05B) at
the bass margin is shifted closer to the left Theme hole 0.02677 inch.

Robbie Rhodes

 [ AA7512b2.png (42 kb 300 dpi)
 [ http://www.mmdigest.com/Attachments/17/06/05/170605_170306_AA7512b2.png