When I launch, which is not often, I do not "dump" the clutch. My technique wether it be a good or bad one has worked for me, is to not maintain a certain RPM like 3k, but to keep it in a range. I basically do just that rev, like tapping the gas pedal. Then I basically "slip" the clutch as smoothly as possible on a rev. Who knows if thats right or not, but its my technique, and it works, if you can remotely understand the way I do it....?