This is an interesting method of keeping bees without chemical treatment. This year i have tried a variant of it on a few hives. I will know whether or not it worked if those hives are alive in the spring.
One beekeeper in Finland claims that he has no varroa control what so ever except massive drone brood removal. He has about 200 hives. He removes one whole size 232x448 Langstroth frame of drone brood from every hive each month if not twice a month, cannot remember. One interresting side plot is that he has small cells and claims the "drone removal" -method did not work well enough with normal cell size.
Same here, but I only have a small number of hives at the moment. I am splitting constantly as I rebuild after a prolonged illness, so I naturally have a lot of brood breaks. Not difficult to stay ahead of them under these circumstances, but I am wondering if I can keep it up as I continue to increase my hive count. I get around pretty well, but I am slow. I am going to have to pick up the pace, a lot, lol, if I hope to keep up in the future.
I am not far from you- about 3 hours NW of the Twin Cities- we're practically neighbors, lol.