If the piece is quite irregular you'll stress the hold - any hold - quite a bit even if you're careful with your speed. Means you MUST have a perfectly smooth surface for gluing, and a glue, such as one of the polyurethanes, which will bond wet wood. Standard carpenters' glue won't do. Have your weights ready to press the plate down tight before you spread the glue. Dry run the process, even though the glue has a good open time.
The differential shrink should not be a factor unless you're going to Turn, Dry Turn. The faceplate and block will keep the bottom pretty damp for a week or two. Besides, if it's a burl, you really can't predict what it's going to do. Sometimes it almost seems to do nothing.
I'd use a chuck, if I had it. If you have a lathe capable of swinging 28" over the bed as Bill suggests, I'm sure you do. If so, use a mortise and some big jaws.