Robbie remarked in 030630 MMDigest:

>[ In general, the bigger the disc (or the wider is the book music),
>[ the more notes are played, and so the sound is bigger -- as is the
>[ price.  Plus an added feature of a disc: a big disc generally plays
>[ longer than a small disc.

Also, larger diameter discs sometimes have more tines of the same note
(as well as more accidentals and greater range high and low), allowing
for fuller arrangements.

An odd twist: sometimes you have a disc which is not half as small, but
which rotates twice as fast, e.g., a Regina 7" disc as opposed to an
11" disc.  This can result is quicker 'repeat' times for a given note,
so that trills may be faster or longer in duration on the smaller disc.

Jack Perron - HensTooth Discs
Peterborough NH
http://www.henstoothdiscs.netfirms.com/