As far as I can recall from reading many tutorials and lessons of sweep picking technique long ago when i was learning to do the same that moving your fretting hand to accomodate the movement over the strings was ok and in most cases most comfortably necesary. Especially if you have small hands and a large fret board. Whatever doesn't caue you wear and fatigue is probably safe too. Yes, rolling you fretting hand, if that is what you are doing is quite safe and practical while sweeping. Or you can be insane and work on keeping your hand stationary and use your fingers mostly...it doesn't relaly matter how you play as long as it doesn't hurt you and it sounds good. Technique is relative, all the best guitarists have their own way of doing things, learn for their example.
Hope that helps any...
Also you have songs somewhere that I could listen to?
