I don't know what he'll play, but I would imagine that this festival is unlike a typical tour stop in that most artists aren't exposed much on these shores and thus will pull out a sampling of all their stuff. For example, while I'm sure the Bards will want to highlight their A Night At The Opera material, they'll in all likelihood cover their entire back catalog.
So there's a good bet Devin will play some SYL material as well. Also on that note, I've read in more than one location that a 2nd SYL album can be expected by either late 2002 or early 2003.
Hope that helps a bit.