A very old thread, but I'll add what just a few have alluded to.
When I started jumping back in the Reagan Administration, we were jumping Mantas and for the longest time, we were taught, for lack of a better term, a one-stage flare, but we were on radio and most of the time we flared all the way when we were instructed to.
Later, after I had been instructing FJCs for a while, we taught 2-stage in class, and not because we were trying to teach a perfect flare to first jump students, but simply because of the near-universal student propensity to flare WAY TOO HIGH, WAY TOO SOON.
But on their first jumps with radio, to avoid having the students flare too soon, starting at about 80 feet, the radio operator would start to say, "Hands all the way up, all the way up, READY, READY, READY, READY, FLARE FLARE FLARE"
The main point here is that the REASON we taught them to do a 2-stage flare was not to teach an optimum performance flare for a first (and, let's be honest, often only) time jump, but to prevent the student from shooting their wad all at once at 50 feet.
So we would tell students to flare to their shoulders at 15 feet, then when they realize they are in fact at 50 feet, to hold there until they get down to 12 feet, and then flare all the way.
Later, as they transition to different canopies, or in later categories where they are refining their flare in the canopy dive flow, we can start to talk about optimum flares. B-license requirements now include a canopy course which I think is a much more appropriate time and place to get into the finer points of flaring, rather than in the FJC.
A first jump student already has a very full plate to digest as it is. They are likely not going to remember very much about flare techniques when they are instead more worried about malfunctions, obstacles, dive flows and so on and on and on.