An odd formula - big swarms and small bait hives!
When i started beekeeping with byed swarms, I joined them. 4 kg was the optimum size to begin. It occupied 2 langstroth boxes. It needed often 3 swarms together.
Modern bee stocks have often 3-5 kg swarms. What you do then when you get only tiny swarms?
If swarm feels the hive too tight, it continues its way next day..