Harry, I my opinion you have given the cell size issue a lot of thought. i agree with most you have said but i don't have the answers to give you . I have thoughts about getting the smaller bees but cannot prove my ideas. I kept smaller bees when i started beekeeping in Missouri. I kept a strain of small black German bees for years. They had one fault and that was temperment. They produced a lot of honey but not as prolific as my Italians. I kept raising queens from her for almost ten years but eventually lost the line. The queen would go right thru a modern queen excluder so i had to use a old wood slate excluder made YEARS ago. I got a interesting call from a Iowa beekeeper complaining about a Missouri beekeepers nucs last year. This Missouri beekeeper sells around 300 nucs a year. The Iowa beekeeper wanted me to give him the source of my queens. Why? Because those tiny queens he got went right thru his new queen excluders he bought last year and laid eggs in all his honey supers. I gave him the name of my queen breeder but plan on checking those small queens out. How about a quote from page 22 of the varroa handbook. In the Indian bee,Apis Cerana-original host to varroa,varroa mites are unable to reproduce in WORKER BROOD. Female mites may enter worker cells ,but will remain trapped for the full pupation period,unable to even lay an egg. This fact alone reduces the mite's chances considerably and new generations can only be produced when drone brood is present in the colony. The quote is exactly as above-look it up-except i added-original host to varroa for beekeepers maybe not aware of that fact. A mite is not supposed to kill its host and doesn't with Apis Cerana. The above is my answer why Apis Cerana servive varroa and Apis melliferia don't. I am a well read beekeeper not a DR. Shiminuki. If i am not on the right track tell me so i can get on with my life. I have got about one more week before beekeeping season starts full time and then it will be late at night if at all i will be able to do bee-L. I think you are starting to at least think about my theory. Bob