The thing I don't like about the Brushy Queen Castle is that they are only two frames for each compartment. Two frames are hard to keep going well, particularly once the summer dearth kicks in. This winter I'm building a bunch of three frame queen castles. I'm hoping that the 3 frame versions are much more manageable in my local climate. I've never experimented with the mini frames, but I guess I'd prefer to stick with one uniform frame size. Got enough bee stuff rattling around already.....

Regarding the screened bottom boards: I had several queens come back and get confused where the entrance was and found themselves trapped under the hive. This happened on some divided 5-frame nucs that I built with a SBB, not the Brushy queen castle that uses a mostly solid bottom. At this point I really don't see a need for the screened bottom on mating nucs, and perhaps even production colonies. Just need to make sure the nucs have adequate ventilation.