Yes, I made these and I don’t actually burn AVCHD or DVD9s at all. So, while I could have probably made an mds, my understanding is that the purpose is to make the layer break location. And that’s not something I’d actually be able to test out, so there wouldn’t have been much benefit of me doing that step. Imgburn usually gives several options and estimates of whether they’re more or less ideal.

And indeed, the Certificate folder is just empty. Sometimes torrent clients don’t actually host completely empty folders, and things like this get lost along the way. Not terribly important, but you can make a new empty folder if it gives you trouble.