Do you remember wether you overwrote the name.vmdk or also the name-flat.vmdk ?
If you still have a *-flat.vmdk with the expected size no serious harm is done.
vmfs-tools from Ubuntu using standard repositories will fail with vmdks larger than 256gb.
Can you use vmfs-fuse to list the files ?
Can you use Ubuntu to do this ? (I assume the Ubuntu sees the VMFS-volume as /dev/sdX1 - change this to your needs )
dd if=/dev/sdX1 of=/somewhere/vmfs.1536 bs=1M count=1536
Then I can check if there is a way to create a dd command to extract the vmdk even if the VMFS-metadata may be dead or partially corrupt.
If that does not help it is still maybe possible to extract the vmdk when it was thick provisioned