I'm not a rod builder but I'm very curious about it and would like to give it a try at some point. With that being said, I've noticed several different discussions on a number of different boards discussing various suppliers and grades of cork rings. What's the deal with burl cork? I see that it's available from a bunch of different sources (i.e. http://www.lamarreelseats.com, Angler's Workshop, etc.) at a pretty reasonable price but know very little about it. Is it a reasonable alternative to "real" cork?