Graham Banks wrote: Xmas2640.abk which is a smaller book - excellent for tournaments, but not recommended for matches or gauntlets.
Thanks for recommending my book.

The concern about matches or gauntlets (with many games between the same opponents) is, that there is some probability of opening doubles if you use the Fritz version with the 'optimal' setting. I am not 100% sure about the doubles risk with the .abk version but I think it is much smaller, maybe like 'normal' in Fritz.
Unlike other books, the Xmas2640 books are a more balanced repertoire, IOW Sicilian and Ruy Lopez not that often and other standard (frequent) openings more often.
http://members.aon.at/computerschach/li ... #downloads
Both the .ctg and .abk versions are created from the same database. It is only for testing - same book for all - not a 'performance' book. But it also represents a mix of GM repertoires up to move number 12 or 14.