Darth Venal said:
Well, it could just be speeded up a percentage. We're not talking Harold Lloyd here. If you increase the speed of the shot by a small percentage it's perfectly feasible to make it work better. In fact, you could speed up most of the action shots in the duel by up to 10% and most people wouldn't notice it had been tinkered with, and it would move faster, as required.

You would definitely notice if watching a PAL version ;)

Speeding up a human will always look unnatural, no matter how you do it because of the way our brain perceives things. If you sped up the twirl by about 4% it would probably be ok for the NTSC version but will play another 4% faster for the PAL version and that's where things begin to fall apart. Don't forget Alec Guinness was 62 when filming Star Wars.