You can pick it however works best for you.
Sweeping/Raking are relatively the same, sweeping you put the effort into making sure you play each note individually, I believe raking is when you pretty much hold the chord and arepeggiate it rather than strum it. I could be wrong there with the terminology and they could mean the exact same thing.
Alternate it if you will.
Tap arpeggios if you will.
It's already been said, but I feel like stressing it.
ARPEGGIOS are just the notes of a chord played in succesion nothing more, nothing less. Simple concept if you know say a major or minor chord play every note in it to get an arpeggio. The more complex the chord the more ntoes to play. The more interesting you can get with the technique used to paly it.