Tried to answer a post yesterday asking about my breeder box with vertical excluder. Daughter changed my computer to Firefox, couln't get it to copy image address, now I can find the original post.

Anyway, this is the box I use. Vertical excluder is rabbetted into front and back wall, and extends from top of box to bottom board. Queen is confined to 3 frame chamber by excluder, bag inner cover, and cleat to close entrance. 4-5 days before grafting, a worker comb is added to queen's to excluder. The other two combs there have to be full....queen can't lay there. Can be full of honey, or brood that won't emerge in the next few days. She has to lay in the comb you give her. After graft, the queen's combs are manipulated. The outside comb is removed to the far side of the excluder, the remaining two are moved over, and another empty worker comb is added to queen's chamber against the excluder. 4-5 days later the larvae are ready to graft, and the process is repeated. This goes on until cell building and grafting is finished for the season.

Just remembered, original thread was wintering mating nucs.