There are other factors at play other than the hive spacing.
With good forage the bees can withstand the mites better than a poorly feed colony through out the
season. What work in one area may not be duplicated in another because of the environmental differences.
I rather solve my bee issues than following other's footstep.
I think the local environment
is an important factor - or even several non-determined factors. I found myself reading an article by Kirk Webster a couple of days ago in which he mentioned Dee Lusby - who runs her operation within the Arizona desert - as being one of the first and most successful 'treatment-free' beekeepers who commenced that approach prior to the advent of Varroa. Now I've no idea how much relative isolation that desert provides, or to what degree the climatic conditions there affect the bees' behaviour - but I would suggest that for another beekeeper in an area with a significantly different climate, and perhaps surrounded by several other apiaries 'within range'- to adopt a treatment-free protocol
solely based on the Lusby's success, would be extremely unwise.
There does appear to be a lemming-like mentality within beekeepers - and to some degree this is understandable - as we're dealing with a creature who's behaviour remains very poorly understood, in part due to it having sense organs far different than our own. All we can ever do is to observe carefully and try to interpret the bees' behaviour in the best way we can ... but always these observations will be filtered through human perception and our own human understanding of the world around us. So there will always remain uncertainty and prejudiced personal observations. Which is why any question related to beekeeping is invariably met with a variety of answers.
But the beginner - understandably - seeks certainty, as they want to do the best by their bees. Of course. And so a problem then exists - precisely because there is no such certainty in beekeeping. Some beginners (thankfully not all) not unreasonably turn to those who appear to speak with authority, and duly copy their methods on the basis of faith rather than their own hard-won experiential experience.
Ok - there is a further complication, and that is 'time-lag'. If a person was to die 15 minutes after smoking a cigarette, people wouldn't smoke. They wouldn't dare to smoke tobacco. But the effects of smoking - the coating of sensitive lung tissue with deposits of tar - may not manifest itself for 10, 20 years ... and sometimes never. It's a game of roulette.
I assume you'll have heard the anecdote of the guy who jumped out of a skyscraper window and as he passed each floor was heard to be muttering, "Ok so far, Ok so far." That's what I hear from people who've adopted a non-treatment approach to beekeeping - that it works - or should I say "It's ok so far".
Non-treatment of Varroa is no different from smoking - you may get away with this approach for a year or two - and then it'll bite you on the bum. You might be able to run treatment-free for decades - perhaps even indefinitely - you might indeed be that lucky. Or you might not.
So how on earth is a person to then decide about
any beekeeping practice, not just about the treatment/treatment-free issue ? That's why I'm suggesting that proven success is by far the best barometer to use. Your own success, preferably (of course), or the success of those local to you. Use what works, and has been shown to work - and treat unsubstantiated or untried methods with suspicion. I cannot see any sense in following the ideas of someone who has a track record of failure - no matter how good the sales-pitch.
LJ