I have 5 20TB HDDs in a RAID array at home, in the real world I get a little over 72 of them. I can lose one disk and have no data loss, though
As for how quickly you fill it up, I'd say that really depends on how much data is redundant and how many backups you want to keep.
I had tried that previously, but on trying it again I realized that I’d missed setting the Color Depth. Apparently this was enough to make it work properly. Thank you!!