I can say that being able to keep the disc's weight under control is an absolute necessity and so the hammer drills still apply. The difference with this tech is that there's no forcing of the wrist extension.
by that point the disc direction and the motion of the hand are basically working together like a sling (a good snap is almost frictionless on launch). this is sort of why the wrist opens... the inertia of the disc forces the wrist open.
The thing i have come to learn is that it is not the pivot as much as it is the raw "edge weight" (aka the weight of the hammer's head) that is really being forcibly manipulated here. This explains why it is still possible to snap without extending the wrist as long as the relative positions of the forearm line up with the body positions and timing.
Hold the bottle near the middle or bottom with the neck angled upwards (~45 degrees). pull the bottle's along the rail with the bottom of the bottle being the front as it moves along the rail. as it passes the critical point, rotate your forearm and flatten the bottle out slightly so that the water abruptly shifts to the front.
Many large handed throwers talk a lot about tumb pinch or thumb push. Basically, as you pass the critical point you want to hold your thumb down and push your thumb forward (this does not mean to point e thumb lower). The end result is a small rotation of the forearm that helps you hold on more easily and is equivalent to the "wrist breaking" portions of a golf or baseball swing.
Think of wrist extension like the break of the wrists when swinging a baseball bat. Your focus isn't really on breaking your wrists, it's getting the bat through. A strong and well-timed break of the wrists will give you more bat speed and hitting power, but if you try to exaggerate the wrist break without proper timing it will be weaker. Wrist extension is a bi-product of good positions, timing, and angles. Forcing wrist extension outside of those things will not yield a significant gain.