That is awesome :) I hope you share at least a clip of what it sounds like farther down the road once you have finished this beauty, I would love to hear what an ancient redwood guitar sounds like.
I remember reading about salvage expeditions in the great lakes (US) to recover huge old logs that had been lost from the century-earlier logging operation in the area. It was similar thing, they were destined to be used for musical instruments and each log salvaged was worth a ton of money. The article went into the science of the transformation the wood went through while aging in the cold underwater.