Thanks, though this leads to more questions:

1. The documentation describes $| as working with the currently selected output channel. STDERR also counts as the currently selected output channel?

2. Documentation for IO::Handle seems to say that
# setvbuf is not available by default on Perls 5.8.0 and later.

The pod for Handle.pm goes on to say that:

WARNING: The IO::Handle::setvbuf() is not available by default on
Perls 5.8.0 and later because setvbuf() is rather specific to using
the stdio library, while Perl prefers the new perlio subsystem instead
+.
[download]

From my ActiveState documentation, it does not look like this is included.

Also, it looks like I can't use garden variety warn calls with IO::Handle, I'll need to change these all to object references? I assume system errors for STDERR will magically know to write to the designated file?