I dont really like symphony x, but when I was learning to sweep someone recommended the intro to Smoke and Mirrors to me...
At full speed that sweeping is quite hard, but I slowed it to 25 % and then 50 % when I had hang of that...the shapes themselves are not too hard and they are good for practicing with accuracy.
When you can do it 100 % then I think you probably have the hang of sweeping, but make sure you master each 25 %, 50 % and 75 % before you try full speed.
So many people make the mistake of going too fast too soon, and although it might sound like you can do it, it wont be clean...by mastering it slow then you will get better results in sweeping when you go faster.