Hmm, I forgot about the proof of stake switch coming, but sounds like its going to be slowly mixed into the current blockchain, so it maybe wouldn't hurt to start now.
The question about the frequency of updates is an interesting one. I've used a fancy filesystem feature to only store differences in the data, so I can have multiple versions of the same blockchain without using infinite disk space. But if a particular torrent gets popular, I don't want to push it off the list when I create a new one. I'm thinking the BTC blockchain should probably be updated once every 3 days or so, because you can sync the last 3 days in like 5 minutes or whatever. Maybe there should be "LTS" (long term seeded) torrents and also more frequent ones. I really don't know how or IF anyone is going to use this.