I've found that when cutting thick jade branches the stump will die back to the next ring. The dead section will dry out and will eventually fall off, leaving a hollow. Carving it and cleaning up the cut won't make much of a difference, although I once saw someone online cauterise a carved area with a blowtorch!
Also well done on taking action on the design early after a lot of consideration. Rather than putting off the decision you now have a plan to follow.
Matt.