dar_manager questions

Hello,

As I'm trying to sort out my archiving scheme, I've got some questions
about dar_manager.

First, let's start with a simple scenario.  Say I have a set of USB
backup drives.  I start writing backup data to drive 1.  It gets a full
backup.  Then, I'm writing incrementals/differentials.  I save off
isolated catalogs from each backup run and ingest them into dar_manager.

Eventually I run out of drives, and at that point I delete the contents
of drive 1 and start over there, deleting the contents of each
previously-used drive before reusing it.

At this point, I would probably use dar_manager --delete to remove the
full backup as I'm about to overwrite it.  That API is a bit
inconvenient (it would be more convenient to be able to pass it a
filename) but it'll do.  Now what happens to all the
incrementals/differentials that were based on the full backup?  And on
subsequent ones?  Do I just need to start a new dar_manager database at
this point?

Now for the second scenario, let's say I am backing up the same data to
three different backup media sets.  At any given moment, at least one
will be off-site.  It is easy enough to base an incremental on the
most recent backup in a set.

But now, what of dar_manager?  Can I safely import these three different
disjoint scenarios into dar_manager?  My guess here is that I'd be
better off having three distinct dar_manager databases.  That would make
answering the question "exactly what drive has the most recent archive
of a given file" a little more annoying (but still doable).  Or is there
a way to maintain these separate chains in a single database?

Thanks!

- John