I just added a Lacie 2big 6 TB disk, but not sure how to configure it best. I am thinking RAID 1 rather than RAID 0, for security over raw speed. Out of the box, Disk Utility describes it as Striped RAID set RAID set size 6 TB, RAID Status Online, Number of Slices 2. Not sure how it is configured.
It's a raid 0. If you want the space cut in half, use Raid 1, which is mirrored. Which means each drive is duplicated. No benefit for editing. I have a drive like that for all the family photos and project archives. But I have a RAID 5 for current projects. Gives you speed and some security. You have to have a minimum of 4 physical drives to set up RAID 5.
If you were looking for mirrored (Raid 1), then you might as well have bought a USB 3 unit. I don't think I'd waste thunderbolt for mirrored.