Looking for some recommendations for a backup storage drive/s for my original 1080 and 4k media for the new iMac 5k. I don't use Raw and/or Red media. This would be separate from my media RAID hard drives used in FCPX, Motion, etc. Would you suggest another RAID setup, Thunderbolt 2 or just simple usb 3.0? Thanks in advance for your help. Ray