The first time around, I blithely assumed that we should truncate as
much silence of the beginning *and* the end of a track. When I
attempted to play the resulting files in sequence, the transition
seemed rushed and unnatural (these are not seamless tracks).

So, I've been investigating tracks from other places, and they have
varying trailing silences (the three I checked ranged from 4 to 7
seconds). What's your preference?