Tip for raising queen cells

A fortnight ago I found queen cells in two colonies and I removed the queen and a couple of frames of bees to a nuc in each case. I left an open queen cell marked with a pin beside it and removed all others.
Usually what I do is check 5 or 6 days later to remove the additional emergency queen cells which a colony invariably makes.
In this case I put a frame of grafts into each colony 5 days after removing the queen and I removed all the natural queen cells I found including the ones I had marked.
I checked yesterday 5 days after inserting the grafts, and one had 7/10 grafts sealed and the other 12/20. The cells are a good size, slightly bigger than those in my cell raising colony. I also found several more emergency queen cells on the frames which I removed. They must have been using larvae at least 2 days old to make these.
This would work well for someone who wants a few queens but doesn't want to go to the bother of setting up a cell raising colony.