Is mv preferable to delete/add from a space standpoint?

[Robert Collins]

Experimentation is the source of all knowledge :)

commit a change using both approaches.
run bzr pack in both test areas and look at the size of the
.bzr/repository/packs/*.pack that result - ignore indices for this
test, as we're trying to find out the compression.

As for --auto heuristics, they can probably be improved, if you want
to file a bug that would be great.

-Rob