DCottrell:
It's worth noting than the 15x14 perfs are actually 14.82x14.08, so extreme care is necessary when measuring.
Incidentally, ACSC rounds perfs to the nearest quarter while SG and others are generally to the half.
Finally, ACSC is expensive, but is well worth the expense because of the greater depth of the included information. You can cut down the cost by buying older copies on
ebay one elsewhere but be warned that they seem to change their stamp numbers more often tha, eg, SG. I have a 1988 and a 1966 copy and their numbers differ between the two and also later issues.