Did that with two PS3s running separate versions once. Close as we're going to get I'm afraid. As far as I know you need a dev kit or special PS3 or something to play the preview version of Zone mode, and very few people have access to it to begin with.

Yes you're right you have to monitor patch progress otherwise you have to start from scratch. I learned the hard way once, on a 0.4mb connection

I'm glad they didn't patch the download itself and that old versions of the game are still available else some of us would never be able to play again. That's something at least