Thanks for the info, guys. Well, I thought that the flow started when the dandelions popped up.
So, I put the hive back into the "standard" configuration, with an upper brood box of foundation and some food. I'll let them work on that for a few weeks, and if the flow gets heavy, I can always reconfigure them into one box again. Or try the alternative.
If nothing else I got from this experiment, it was two healthy hives from one. Plus, I learned how to find a queen in a very crowded hive without marking!
And I noticed, either these hives are more calm this year, or I am.