Rainboe thanks for those good questions.
Yes it does rely on a consistant approach path to the aiming point, but no more than any other approach.
Sometimes you do get a gust of wind or some thermal lifting at say 100 ft and suddenly find yourself aiming a little further down the runway than you would have liked, and don't have enough room left to get it back on the correct path to your original aiming point without risking an unacceptable increase in descent rate so close to the ground. In these cases I simply move the aiming point further down the runway that equates to a new 3 degree path to the runway surface (within reason of course) and move the reference point the same distance. With practice it becomes quite easy to do.
Regarding various flap setting. Yes you are correct that that will have an effect on the glareshield cuttoff angle. The change will be the same as the change in approach attitude. The actual change is usually only a couple of degrees. cot 2 degrees equates to about 20 ft in horizontal distance. 4 degrees in attitude change varies the reference distance by around 43 ft. 43/20 = 2. So a 4 degree change in approach attitude will change your flare height by only 2 feet.
Regarding seating position. In the aircraft I fly, there isn't that much room to manoeuvre. You have to sit high enough to see over the control column to the EHSI, but low enough that I my arm is not too high relative to the control wheel and my legs are comfortable on the rudder peddals.
Yes it is rather mechanical. Consider it a framework from which to build experience and a feel for the aircraft. I am now at the stage where I can feel where the wheels are once in the flare and I know that when I get that sinking feeling at 50 - 30 feet I am going to leave the thrust on a little longer during the flare, and when I get a sudden gust of wind and I'm suddenly Vref+15 I can bring the thrust to idle much earlier than usual. But when the visual cues are limited, or I'm landing on a 30 metre wide runway, I can assure you that seeing the reference point passing under the nose and beginning the flare before it actually feels like time to flare has saved me from a harsh landing on numerous occasions!
019360 I know what you mean too! You can't beat looking at the windsock! and having a feel for crosswind landings and being able to apply just the right amount of rudder to align the fuselage with the runway while cross controlling with the right amount of aileron to keep the wings level is one of the real joys of flying.
Like many things, it can seem complex and convoluted when written on paper (or computer screen), but in practice it is oh so simple!
And just repeating the flare technique is a framework from which you can build experience and refine with time. It is also something to fall back on when you're tired and/or the visual cues are lacking.
