64-bar and 48-bar dances are problematic because of the piece count.
Basically it's the phone-number problem -- short term memory works
best remembering a maximum of sevenish-eightish pieces, or chunks.
Above that the dancers need to concentrate harder, or be reminded, or
redefine a chunk. (Make swing-circle-swing an entire chunk, for
instance.) I find that's a problem with most of the 48-bar dances I've
run across.
I've only danced one 64-bar dance, and there the caller never dropped
out. It was at a dance festival.
-Chris Page
San Diego