Well, the hardest exercises make the steepest learning curves I guess. I'm learning to sweep left-handedly but there's not less sweep to it than a tired kitchen porter on tranquillisers. i have to slow right down, probably less than a 5th of the pace of my right handed play. It's quite informative actually, I'm learning again what things used to be hard and what my original progress may have felt like. On the otherhand progress is probably going to be faster 'cause at least I know some pieces and shapes to play.