I've never really understood interleaving. I think it's also known as sector skew and is something to do with the offset of disc sectors between tracks. So an interleave factor of 0 means that sector 0 of each track is next to sector 0 of the track before. With an interleave of 1, sector 1 of a track is next to sector 0 of the previous track and sector 2 of the following track and so on. It's a way of making disc operations faster but I don't really know how it works so don't take my word for it!

Anyway, I'm quite happy to accept SJ Research's advice on the matter so we are ready to format!