The story so far... I commented that I'd been taught to lean first from the torso, either forwards, sideways or backwards, and that then the free leg needs to follow. I posted some slomo of Luisito Ferraris just to check if what I'd been taught was actually how tango is danced: the torso-first movement is visible, but only just.
I then posted another video in which torso-first is very exaggerated. This led to an interesting comment from Tango en el Cielo that when Ricardo Vidort danced his stance inclined forwards – 'he really gives his upper body to her'. I checked out the YouTube clips of him, which reinforced my own memory (from video) of how he drove forwards with the upper body. Miraculously a new clip had appeared, filmed from very close by. Although this has limitations it means that it's much easier to see details. I hope Jessica Grumberg, his partner in this video, will excuse me for quoting a very brief extract from it in very slow motion. & I hope very much that she has more video like this.
The first few seconds shows just how upright his posture was. He's relaxed, joking, but there's no hint of round shoulders. The back is straight from the lower back upwards, the head high, which means the chest is naturally well out. The second and third few seconds show how far forwards he leaned when he led forwards. He leans so far forwards that when he steps forwards his foot is still more or less under his shoulders. His partner is in no doubt what is happening!
It's quite a simple dance, nothing elaborate, but gives the sense that he's creating the music rather than following it. I always get to know the music better by watching his dance to it. In the dance of Junior Cervilla & Rachel I feel the music is little more than a background beat: substitute a different piece of music and I think the dance would be much the same.
Anonymous, you asked about how the old dancers led; I hope this suggests an answer. It looks clearly as if the chest moves before the foot. As to dancing close with shorter partners, I've been taught never to bend down, always to keep upright. 'Let your partner reach up to you'. One short partner told me she really hates leaders bending over her.