How I've been doing this is that I have 2 (sets of) backup people. The first set has access to the repo, but can't decrypt. The second set can decrypt (i.e. I have their pubkeys imported), but don't have access to the repo. I've chosen the people such that it's unlikely they collude against me, but in case something happens it's likely they'll be able to get in touch with each other.
There's also other possible approaches: e.g. instead of building a dead man's switch based on the encryption, you can build a dead man's switch based on the data. I.e. you'll use their pubkeys for encryption, but the repo itself is behind a dead man's switch.