Well after around 2 years of trying I've finally given up small cell combined with bond method, today.
First year or 18 months it went pretty well, then things started sliding. Increasing mite numbers, hives dying. As per the plan I let them die, expecting a few to survive to breed from.
However ALL 9 of the hives have been overwhelmed by mites. The 21 nucs, even just a few weeks ago were looking pretty good. But checked today, every last one of them is either dead or so close it doesn't matter. Amazing how fast they went down.
I've actually done everything right, religiously, even. I think there's 2 main reasons for the complete failure. One is our winters here are mild and the bees have brood 365 days per year. There is no brood break, mites paradise. Second, we have only had varroa here 1/2 as long as you guys in the US, and there has not been the time for our bees to build enough immunity. I've used as many different strains as I could get, but end of day, they just cannot handle mites yet without help.
I'm still very interested in ways to be treatment free and it's still a goal for me. So I'll still be hanging out in the forum.