So in the bottom box will definantly be the queen, in the top box will be half the brood covered with nurse bees? Won't the brood in the top box be non viable to produce queens because they've been shaken?
In addition to the comments above, if you end up with a nuc sized walkaway split making their own queen cells that is not good beekeeping practice in my book. By default, I had a large colony re-queening themselves by making emergency queen cells. These emergency queen cells were normal size whilst emergency cell by a small colonies have always been small. Size of original colony and timing as pointed out above is imperative.
Well, after doing Pagden last year, I did two nucleus method (walkaway) splits this year and one of the original hives has already made a super of honey. So the method does work. The second hive murdered my new buckfast Queen, preferring to make their own emergency queen cells.