Here I'd be replacing the too small SSD. For me the lost time means I'm swapping in the 120 buck 500GB SSDs and then for backup my choice of imaging or file syncing.
Portable drives do tend to be the worst place for storage. So that 1TB could be a good spot for the first backup copy. Then you need another place for the other backup copy.
To keep a good backup you need 2 or more copies. Why? Because if something goes wrong during backup you could find yourself without any backups. That's why there's a backup to the backup.
My PC has 8 GB RAM and three hard disks:
(a) 160 GB SATA
(b) 1 TB SATA
(c) 500 GB Portable
OS Windows 10 has been installed on 160 GB fixed drive, which has only 56 GB free, and therefore, cannot accommodate 200 GB data. Hence, data has been stored on 500 GB portable drive, and 1 TB fixed drive is empty.
In these three hard drives, I wish to store (a) system files (b) data (c) Windows File History and (d) system images.
What could be the best way to organize these in hard drives?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic