I assume you are planning on the two drives to mirror them in case of failure? It looks like a pair of 16 TB drives will cost about $700. 4 TB WD Blue drives are only $90, so you could get 5 of those and put them in a raid 5 to have 16 TB of usable space for only $450.
I’ve had 3 1 TB blues in a mixed raid5 and raid10 setup for several years now since my OCZ SSD started randomly swapping blocks around, and have been quite happy with it.