Can you make any kind of a saw cut to the center of the log, for the entire length?
This might prevent many cracks from beginning on their own.
People here try so very hard to prevent cracking. The First Nations native carvers can ignore cracks most times.
If pieces break off from cracks, I glue them back on and come back tomorrow to carve.
If my translator is behaving properly, I suggest that the washbasin be a separate piece of wood.
That way, you can replace it if it cracks and keep the wash stand.
It will look beautiful. Very hot wax will soak into the wood and seal it very well.