Jim Gilbert & Karin Clark: Learning By Designing, vol 1, is your best bet for comparative studies of the art and carvings of the Pacific Northwest coast.
Next would be anything from Bill Holm and Hilary Stewart. The "Holm Constant" is a definition of the most comfortable hand grip position on an elbow adze.
The "Kestrel Constant" defines handle size. I have learned by experiment that differences of 1/8" matter by the end of the day. Both for adzes and for crooked knives. My next (and bigger) elbow adze is on my bench.