Similar to my OP above, I still have four separate locations that each hold a piece of the 2 of 4 information I need to restore the wallet. This is intended to be very cold storage, so inconvenience to spend is good.
The information I would keep at each site is:
- The wallet seed phrase of one of the four wallets that are part of the multisig wallet. Each site would have a different seed.
- A paper containing the QR codes for the four master public key of all four wallets, and the text version of all four in case a QR code reader is not available on the device I need to restore the wallet to and entering the key by keyboard is necessary. A copy of the same page could go to each site.
I think this is a good setup because information about all four wallets that make up the multisig wallet is needed to create any of the individual signing wallets, but the public keys can be leaked and it's ok because they're public keys. It's easy to create a document that could be printed with the qr codes, and it doesn't matter too much if they fall into the wrong hands (I think) as long as the seed phrases are still safe. The only potential downside I see is that the presence of four qr codes / public keys could tip off an attacker to the arrangement of the wallet as a 2 of 4. However, they still wouldn't have access to two of the four pieces. And if they did manage to get that, I'd pretty much be in trouble no matter what system I used.
I lean toward this method over some of the other suggestions because the only software that's needed to create the backups or restore them is electrum wallet. I wouldn't have to track down multiple software projects that may or may not be compatible with today's version of those projects, or could be defunct, and get a bunch of software packages back in alignment before being able to restore my wallet.
Does anybody see any major holes in my thinking?