Barit - Your experience fits with what a lot of other people have found out. You don't have to be that close to feel the effects of CB's. Scouting through the reports of others flying at the time. Most just got down as fast as they could. Sadly a few didn't consider it a problem.
One pilot (Mr He Zhongpin) died after being sucked up. His body was found nearly 50 miles from where he had taken off. He was found by the Westpac Rescue helicopter. His logging system failed at around 6000 Metres.
scooter boy - Ewa Wisnerska had a tracklog system on board so her altitude and location was recorded. She went up to 9947 m, according to the tracklog. And had vertical speeds of +20 m/s up, and -30 m/s down during her flight.
No doubt more will be revealed with time.
Astral