Jim and Van,
I did as you suggested and shook every single frame, in all three of my three of my swarming hives. I removed appr. 30 queen cells.
Most were older, empty cells. Some were sealed, but empty or dead. 5-6 were viable, and the queens started emerging after I put them in a little container I had on hand. They are now in my tiny alcohol bottle.
I left the best cell in each hive, although I worry that they might be empty or duds like some of the sealed ones that I removed. One of the queens chewed her way out and went loose in the hive. However, it was the selected cell I had set aside to keep, so all is well.
How long should I wait before checking for eggs? 2 weeks to harden, mate, and start laying?