The reason your hands can't follow is because you have only 99pp. If you want to practice higher ARs at your level, playing Hard Rock is the main option. You won't learn much from watching others play.
https://osu.ppy.sh/s/43166
https://osu.ppy.sh/b/125944?m=0
https://osu.ppy.sh/b/249438?m=0
What I used when I was trying to learn streaming
Well if you insistbigfeh wrote:
As for alternating, start on slow streams - there are a few practice maps I'm sure someone will post
https://osu.ppy.sh/s/43166
https://osu.ppy.sh/b/125944?m=0
https://osu.ppy.sh/b/249438?m=0
What I used when I was trying to learn streaming