I have several cherry burls on hand, but none, so far, have presented that big a void to deal with. Looks like you made it through the process just fine. Well done.
How did you mount it? The void looks large enough that a chuck probably wouldn't hold it in either compression or expansion. I'm guessing a waste block.
However you did it, you did it beautifully. Often the wood that is completely unusable for anything else makes the very best turnings.
I actually compression mounted it on my stronghold chuck.
The tenon was as wide and deep as my jaws would hold.
The void grew visually as I gently removed most of the tenon while it was mounted on my cole jaws.
Needless to say, it was an intense project.