Thanks for the link.
As I’m making some crown boards and clearer boards at the moment I might try a couple of queen excluders with drilled holes round the edge, just to see. I don’t know why Dave Cushman says that this type of queen excluder will not works if there is drone foundation in the supers? Surely, if the queen wants to lay in the supers she will pass through the board no matter what size cells are there to greet her.