[G4] Options for adding disk space to Power Mac G4?

[Eric Smith]

I have a Power Mac G4 ("Sawtooth" model) with these attributes:
1.0 GHz CPU (Sonnet upgrade)
1.3 GB RAM
USB 2.0 card
2 internal ATA drives:
  - 20 GB drive w/ two partitions, one has OS 9.2.2 and the other
    has 10.4.11
  - 57 GB drive at this time mainly holds iTunes database
    (~18 GB and growing slowly)

I want to install Leopard on this system, just because it's the
latest and greatest and I want to play with it, and also to try
out Time Machine. I would do an initial install and not disturb
the contents of the 20 GB drive. My options as I see it are:

1. Install Leopard on the 57 GB drive. Of course this is possible
but I don't like the idea of the OS competing with the iTunes db
for space; there may be sufficient now but eventually there will
be a space problem, and backing up the db will be more difficult.

2. Install Leopard on an external Firewire 400 or USB 2.0 drive.
I think this would suffer in performance vs. an internal drive,
since this machine has ATA/66.

3. Put the iTunes db on an external drive and use the 57 GB drive
just for Leopard. This could be done, if the external drive has
enough performance to stream iTunes (probably not a problem).
It would seem a little inconvenient to have to have the external
drive powered up every time iTunes was used though.

4. Replace the 57 GB drive with a 120 GB drive, and partition it,
say 40 GB for Leopard and 80 for iTunes. Unfortunately there is a
128 GB limit for drives on this system, unless a third-party driver
is used - and from what I understand that is not without problems.

5. Add another internal drive to the system. Unfortunately here,
two ATA drives is the maximum. Another drive would require a PCI
controller card for ATA/133, SATA, or SCSI, and probably some
mounting brackets, etc. While this would offer the best performance
it is definitely the most expensive option, and there's still that
128 GB limit.

I'm leaning toward 3 or 4, but I thought I would put it out to the
list to see if anyone has an opinion on the advantages vs. tradeoffs,
or any ideas of other options that I have missed.

Thanks,
Eric