Most claim that a DEEP sized box works best. Maybe it does? As I posted in the other thread, I have had swarms move into nucs. In fact two swarms moved into nucs IN my shed, the third swarm moved into an assembled medium.. assembled.. It was on a bottom board with a tele cover on it upside down. Both nucs and the medium ten frame were all in location and set up as they were. When the first swarm moved into the nuc, I waited till late evening and moved the nuc to the yard with the rest of my nucs.. a few days later I had to move a second nuc.. about two weeks after that, I had to move the medium ten frame out to the yard.. I can't complain, they split themselves FOR me, IF they were mine.. I think they were, but After extensive searching I could not locate a hive that had queen cells....
MY OWN personal belief, is that the bees will move into what THEY like the best.. If you have a deep sized box set up properly, there is a good chance they will accept your invitation.. If you do not have deeps, then use what you have!