First two collections from storm cloud gave me 1 wind stone each time, so I thought I was doing great. The next two collections gave me nada. I am resigned that this is a storyline event, so it will just take time and patience. Actually that's probably better than the last couple where each part was timed and I worked hard to make sure I got them done in time. I'll try to slow down and enjoy the journey.
Update- now 4 collections in a row without a wind stone. I'll keep checking every 4 hours though. Eventually I'll get 10 and can finally finish part 2. No worries. We'll have another event to start on Thursday to keep us busy.