If I were you I'd do exactly as Mike suggested, making sure to leave enough heartwood to make an all heartwood bow if possible. If you clamp it down it should dry fine, no twisting or lateral bending.
Also, if you've never chased a heartwood ring before, I'd practice on a similar type of wood (mulberry or black locust) first. TBB 1 explains how to chase a ring pretty well IMO.