i've picked Gypo's brain before over some time now, just for the reasons that Daniel stated. This merging of the strengths and understandings of the 2 outlooks, sterategies etc.
i really use fiber pulling a lot, and that would mess up some of the money end of the log, if i had lumber concerns. Usually i try to exercise control over direction and speed, to have greater command understanding of the process, less ground concussion, less spring poles (less side growth, less spring poles in woods ?) etc. Also forcing more fiber pulling, by loading to target with wedge and line to fatten/strengthen hinge- giving more fiber pull(wedge/line direction would either go to oppose lean force some, or to target; i think that only pulling to target strenghtens hinge). But the tree has the same force either way, i really rely on the brake force and stretching of the fibers for this (that in turn demands transfer of this load to stump and roots, so they must be wound, and can rip a water pipe etc. if it is tightly wrapped in the roots, as it takes on this load etc.).
Taking that sideways into the tree, i use the fiber pull the same, sometimes forced hard, so come out further from the parent, as not to let the same fiber disruption have a chance to travel into parent stem being left.
i think that the fiber pull/hinge strength is determined at first folding, without aids; the shallower the lean then; sets it's own hinge weaker (in addition to having to travel further on it, and immeidately hit higher loading than a steeper leaner in first degree of movement); so a straighter vertical tree or branch balance would give less fiber pull i think.