I'm not savvy to the various common roll types.  I've searched
the MMD Archive, but searching 3700 roll postings was impractical.
Is there an on-line primer on roll types and compatibility?

Admittedly my main interest is for my 88-note 1920s Hoffman piano
with a "Standard Player Action", and also for my 1923 Tangley calliope
which uses 65-note A-rolls to play 41 of the 43 keys.

All the piano rolls I've found at yard sales, although having minor
differences, seem to work in my player.  I've never seen a 65-note roll
aside from the five 10-song Play-Rite "A" rolls I got with the Tangley.
Are there other types of 65-note rolls, and are they compatible?

I hope someone can point me to a source on this, rather than having to
write a treatise for me.

Thanks in advance.
Stan Harrison

 [ For a starter, see the information offered at the MMDigest Media
 [ site: http://www.mmdigest.com/Gallery/MMMedia/identifying.html 
 [ -- Robbie