For home backup I'd consider just using a single drive. You could also get a library that has an older / smaller drive and replace it with an LTO5. The recycler I go to often has this: https://www.ebay.com/itm/Quantum-Superloader-3-L700-SAS-Tape-Drive-LTO-5HH-U... -J
I actually have a LTO-5 drive now, and might be able to get a 2nd one. Coworker hooked me up with a Fibrechannel card and it's up and running on my Debian server. The specific library I found was the most dense scalable one. We have one at work, the mechanics seem totally crappy and weak, not like the StorageTek bohemouths I used to work with. But I noticed that the bad-ass IBM library I really like it's giant, and holds all of 200 tapes. Meanwhile the ML6000 and it's similars (all made by a German company) stash that many tapes in a much much smaller space. There are huge gaps between the columns of tapes and what not. The IBM one though you can keep bolting cabinets side by side and then robot will continue down -- that is sooooo cool. If I had a basement... - Ethan