Rick, I have my fingers in the QR for the kite (c-loop) during launch (I hook in and sheet out while launching).
The QR on the leash would come second in my situation, should things go real wrong.

I activate the stopper quite frequently while riding. I use the new Waroo bar with the dynamic stopper on it.
I always push it away (total depower) before unhooking for a trick.
It is set to total depower while launching and landing, as well.
Having a stopper set to full power during a launch/land would be a bad idea, for certain.
Although from what I have seen, the Best system would depower given where the leash attaches (center lines), I still push the stopper way out before launch/land/unhook.