Gregg Blomberg (Kestrel Tools) has been collaborating with both the big and little names among the Pacific Northwest Native carving community for nearly 40 years.
It appears that there is a nearly ideal handle size for carving tools. " In a fist grip, palm up, the tips of the second and third fingers should just
touch the fat ball part of the thumb." I find this to be a starting blank (knives, elbow adzes and D-adzes) of 7/8" square for my big hands with long fingers.
That's a nearly 10" span. I believe that 3/4" would be fine for hands of average size.
What I never see is any consideration for the size of handles for long blades, single bevels = nice looking, finely crafted knives from the many individual bladesmiths who haunt this place.
Maybe, the Kestrel Constant (as I call it) doesn't apply. But, does it?
Even in the case of an elbow adze. There is a nearly ideal placement for your hand = the "Holm Constant."
While I have spent no more than possibly 5-6 years exploring the designs and applications of the wood carving tools of the PacNW,
I must come away with the notion that the shere geometry of the shapes is much more important than I imagined.
Of course, they have had some thousands of years to have messed around with what works and what doesn't.