Hello Mike & All,
I would think 3-4 hours should be enough time for the bees to figure out
they are queenless for installing cells. Introducing cells is easier than
mated queens. Most commercial beekeepers install cells at dusk.

You get faster  acceptance of cells & queens in my opinion if nucs are made
up from frames from different hives.

My two cents worth.

Bob

-- Visit www.honeybeeworld.com/bee-l for rules, FAQ and  other info ---