Hi Nigel
On another site I'm involved in a discussion about casting style, more exactly about a distinction between style and substance of casting. Roughly, the idea is that underpinning all practical functional casting we all need to do the same and the physics and fundamental mechanics are the same. Among casting teachers there is also a debate about teaching a 'style' of casting. Most casting instructors try not to impose a style, their style, on their clients. (The idea is tall thin instructor Jim teaching short fat Bob - Jim's casting is about long flowing movement - Bob has shorter arms, shorter levers. What's makes the best of Jim's physique may not be ideal for Bob.)
The guys in those clips are among the very best light line distance casters. Rajeff is a champion tournament caster, with heavy single handed rods. Hartman really opened the eyes of some top class casters, his style has been very influential over the past few years. In a sense they represent the extremes they way they cast. Both are throwing #5 lines in those clips but the way they do it is very different if you look at the details - lots to be tried out.