I sure have not done as much teaching as you have. But I've run across a lot of folks where the flinch thing is a big problem. For them at that stage speed is the last thing on their mind. They simply want to increase their accuracy. For them at their level I feel that holding the trigger back long enough that the release becomes a separate event is a valid idea. Speed can come later once the basics are ingrained. Initially it's mostly it's a "trick" to take their mind off the big BANG! and kick to the hand so they perform a nice smooth stable trigger pull without a flinch. Later on once the flinch is gone it becomes "just" a proper follow through style.
Of course once they get this into their head and the group size is small and tidy then they can speed it all up and blend it all so it flows. And once they have a nice flow it can speed up more so it flows faster. At least up until the flinch comes back. Then they need to back up and get smooth again. Then become fast more slowly this time. As they do this the point will occur where they are easing the finger off the trigger and allowing it to reset as the gun is stabilizing at the end of the recoil or just a hair after.
For the local speed steel events I actually find myself easing off for the reset as the gun and I start to swing the sight picture towards the next target. I don't really give much thought to where in the recoil this occurs under these conditions because I typically shoot rimfire in the morning to wake up and center fire in the afternoon. The recoil is so different that it makes it hard to think about keying it to anything to do with the recoil.
