partitioning 4K 3 TB USB hd for 64 bit Ubuntu 11.10

[CJ Tres]

This install episode has been rather convoluted but I believe I've 
included all relevant info. I've been going 'round and 'round for a 
couple days now.

I have, several times, tried to partition and install on this disc.
I've used gparted and Parted Magic which are two programs that handle 
gpt partition tables to partition the drive before install every time.

Last time, I made a 1 MB partition and set the grub_bios flag as I was 
told that Ubuntu would use the partition if necessary.
The / partition was about 74 GB, 2 GB for /swap and the remaining 2.3 
(or so) TB dedicated to /home and I made a small /boot of about 256 MB.

On running the installer partitioner it reports the wrong sizes:

SCSI9 (0,0,0) (sdc) - 375.1 GB Seagate GoFlex Desk
                    128.0 kB        FREE SPACE
      #1            131.1 kB    K   biosgrub
      #4             33.8 MB
      #5              9.9 GB
      #2            366.9 MB
      #3            364.8 GB
                     57.3 kB        FREE SPACE

Rebooting into my Natty install I issued df -h and see:

Filesystem            Size  Used Avail Use% Mounted on

/dev/sdc5              73G  180M   69G   1% /media/_root
/dev/sdc1             992K   24K  920K   3% 
/media/f4948c28-fdee-4bc1-a694-2d311fe0037f
/dev/sdc4             250M  152K  237M   1% /media/_boot
/dev/sdc3             2.7T  202M  2.5T   1% 
/media/87c1e48b-0f88-471a-89fd-58fa9dce5d35

...which is as it should be except the 2 G swap isn't showing.

My hardware is not efi/uefi and there will be no Windows on the disc or 
the machine.
I'm trying, this time, to install from the alternate 64 bit dvd media.

Previous attempts with 32 bit refused to install grub, either to the 1st 
disc (/sda holds only Natty) mbr or to the mbr of the 3 TB disc /sdc.

This was one of a few attempts - a couple with mbr partition table 
-until I discovered I need gpt to recognize/make use of the whole drive.
Not sure but I believe I also attempted it with gpt table also.

What can I do to get this install happening when the Ubu installer is 
telling me lies?

In case this matters:

I did manage to get one 32 bit install completed (I think) from the 
desktop dvd media, after the "cannot install grub" complaint, when it 
gave me the option to place grub elsewhere. I told it /dev/sdd (the 3 TB 
drive) when /dev/sda (the Natty install) failed and it seemed to be ok 
with that.

But upon running "sudo debconf-show grub-pc", the "grub- 
pc/install_devices" line showed only the /dev/sda drive.

I then booted to the 11.10 install media and ran:
sudo grub-install --boot-directory=/mnt/boot, twice, once with /dev/sda 
and again with /dev/sdc as the targets (both had been mounted on /mnt 
first).

Both commands exited cleanly and were reported as "successful with no 
errors".
But..

Looking at debconf-show grub-pc, again, only sda was showing as having 
grub installed.

So anyway what's going on with the Ubu partitioner reporting incorrect 
partition sizes and what black magic must be invoked to make this 
install happen?