I am now reading this pruning book, recently translated from French, that presents a quite intriguing perspective on pruning, vine balance, sap flow and trunk disease. This new pruning approach is growing rapidly in use, in France and now in CA.

Could it be that the pruning techniques now most commonly used are very damaging to our grape vines? The book is well illustrated, which really helps, at least for prune addled me, with understanding the pruning recommendations. 
https://boardandbench.com/products/grapevine-pruning-manual-for-the-prevention-of-trunk-disease?_pos=1&_sid=487efdc95&_ss=r