Hi,

Whenever you are practicing sweeps, you do not necessarily need to pick with any more force than what you normally would use. In fact, doing so can cause extra tension in your picking hand, your arm, and your shoulder. This will ultimately lead to bad use of energy and will affect your picking technique.

The main thing with sweeps is practcing slow until both hands are coordinated with each other. If one hand goes faster than the other, your playing will be off.
This is because your muscles have not yet memorized the positions and movements they need to make.

So, start by playing slowly until you feel comfortable playing..then use a metronome to get things more perfect and precise.

When rolling your fingers, make sure that when you play a note and are rolling to the next...your fretting finger mutes the previous note by remaining on the previous string in a relaxed position. (Only putting enough pressure on the string to mute any noise that could ring out) Also, make sure to mute with your picking hand. I would suggest using your thumb to mute it, as opposed to your palm. With proper muting, you can eliminate how your arpeggios blend together or sound like a strummed chord.

Good luck!