Here's the thing, the G-360 and 450 will be fanless as well. you need to size it big during the short-term spinup current, but after that it sits at <30% load.
You can throw 2x2TB Reds into a mirrorset -> redundancy. Expansion via adding further mirrorsets. or you backup the 2TB of data and move to a new 6disk raidz2, on which you can upgrade via replacing existing disks with bigger ones.
You can throw 2x2TB Reds into a mirrorset -> redundancy. Expansion via adding further mirrorsets. or you backup the 2TB of data and move to a new 6disk raidz2, on which you can upgrade via replacing existing disks with bigger ones.