Very good link!
i think a hinge is a machine, to usher all that weight x all that length (lever, with weight on end; pulling at hinge) x any accelerated speed into a target adjusting for head balance etc. A finely tuned machine can be a beautiful thing to gracefully usher such power. i think unless you want something to specifically fly away from you (like in tree) or bust through limbs etc. (using available force to your benefit), you should work on walking a hinge to a point of failure, and not cutting through it. i look at precut condition as 'hold', cut 'fall'; hinged as 'fhold'; somewhere in between.
As long as the tree holds on; you have some control over speed (impact) and direction. When the faces of the 2 cuts meet; the machine of the hinge must shear or sieze, so a wider face cut can delay this, and give the machine command to hold on longer. Thus, you can more precisely control the direction, and make land softer with way less damage/ more forgiveness.
The facecuts must not cross each other, for this (as Dent puts it); makes a face within a face; and the machine of the hinge is less predictable, and essentially micro face cut sometimes. Like in a kerf cut; imagine the faces slamming shut immediately and all that force and leverage building up, wanting to explode in release; that is opposite of wide face. The hinge is a gravity powered machine to usher all that moving mass and leverage of the tree to the ground; perfecting it will make such a positve machine; with real power, precisely tuned.
Now, if you can take all that, and pull (or lift, or both)the tree (or limb) manually into hinge sooner than it would naturally(with more fiber holding), it can have more control through the sweep, and then manipulate the holding fibers from side to side to adjust for head balance, and brushing other trees on the way down, ushering into the exact horizontal focus of both corners of the hinge/ facecut.
Some guys, horizontally center punch the hinge, to eliminate the least elastic part of the hinge. This gives a nice sight hole, leaves more flexible fiber as control, and eliminates much splintering up the log (at highest yeilding end!)in the logging industry. Though it drops the amount of usable fiber so is best only in healthy wood. It also, lessens the pull of holding wood at the corners i think, as the cornes of the hinge don't have that center 'post' to leverage the pull of the holding wood through to cross-effect the other side. For as in many things here, the left pull of hinge; limits the right leans pull. So if it is leaning right and will fold forward at 500 fibers, then scheduling 350 of those fibers to the extreme left corner of the hinge, can act as/ or compliment a high leverage forward/left pulling line to bring off balance tree evenly forward.
i agree with JP on coming right into the apex, but there is a warning with doing that with a conventional hinge. In that hinge, if you cut through the hinge too early, it splinters, or siezes etc. and it is cut through flatly at the apex, that bottom flat face can deliver the top slanted face into your lap with all relevant force. The reason for coming up 2" from apex in this cut is so the resulting 2 " step would be a positive catch/ lock to maybe save a life or limb. The other 2 cuts are machined with the bottom face slanted down, that would usher such an incident forward and not back; so attacking fibers as he suggests is safer i think with them, though i do as he does on conventional when i use it. i just make sure there is no other compromising factors/ hinges/hangups etc.. i always say"You don't want to make 2 miss-takes at once!". So if you can recognize/ weigh them out, define them, you can make informed decisions as to 'forgiveness' levels.
i love Dent's book; have practiced all this on the ground, and now use it in the air, to hand off limbs into the rigging gently with the hinging technique he presents for stump cutting. The holding wood is always scheduled on the top, wide nothches, not crossing, whose focal point is angle i wish to move limb. We pivot many things off roofs, through wide sweeps, with hinge as an extra/detatchable support line working in tandem with the rigging line. There is less rope stretch like this because there is less force, pulling down because of hinge carrying some weight, speed/ impact lessenned and any of the total force moving sideways is not pulling down on rope. Also this technique can be used to prestretch the rope gradually before tear-off of hinge. After the hinge and length between it and the rigging line usher the head off the roof, (sometimes 180degrees), the hinge is cut and the heavier head goes down into the yard and lifts the butt up. If the riging anchor, and loads hitch point are plumbed in line at this point (detatchement), it won't jostle and jump around. The the butt end becomes a buffering ballast to head falling. Now if ya reach around under load and hitch to pull side, you might be able to get that rigging line pulling tight to torque that head around compounding all that action, getting confident even closer to the roof.....................
After all they are both just manipulating fiber and face( i think of the face also as a tire chock that is removed, so force may flow); to buffer and direct force - the more you learn on one, the more you can cross over to the other. Exactly the same but diffrent!