Risking 1 BTC to test a new (old) way to securely backup my seeds. I will delete if against the rules.

I want to test my Bitcoin seed backup system to see how secure it is. I have placed one (1) $BTC in a wallet and I have encoded the seed using a freely available book in plain text as the key. This way I can save the "locked" seeds in plain sight and replicated across multiple cloud backups, etc. I can even share a hint for myself in case I forget the "key" file. The "key" file is unchanging and part of an archive in the public domain. Anyone can literally download it right now.

Is this method safe when only I know the key?

Hint: Firefly

1. 1144:26 (1,3) 1264:42 (1,3)
2. 949:60 (1,5)
3. 1277:42 (1,3) 2146:21 (1,1)
4. 807:19 (1,4)
5. 2611:34 (1,6)
6. 2643:3 (1,3) 663:55 (1,3)
7. 1319:15 (1,4)
8. 1127:8 (1,3) 2121:35 (1,4)
9. 2123:41 (1,7)
10. 134:49 (1,4)
11. 2271:41 (1,4) 2318:12 (1,2)
12. 2349:3 (1,2) 2349:11 (1,2)

As you can see, a thief would have to guess what the numbers mean, then guess what key document is, and finally make sure they are accessing the correct version of said document since the document might be available from multiple sources, which may alter it just enough to make the above information useless.

Thoughts?

PS: The point of this is to find an alternative to paper backups. This was brought on by the recent freezing event in Austin where paper backups of a few of my wallets might have been destroyed thanks to a burst pipe. So, I have to look forward once I get back.