Apivar timing math — working back from winter bees, what's the real drop-dead start date?

Six years in Flanders, and this season I'm switching to Apivar after two formic summers. I want to sanity-check my timing math because amitraz strips are a 6-week commitment (label says 42 days, up to 56), and the supers have to be off the whole time — no exceptions, it's not a food-safe-with-supers product. My reasoning: the bees that survive winter are raised from roughly mid-August through September here. Those winter bees need to be reared by healthy nurses in a low-mite colony, and the fat winter bees themselves must not be parasitised in the cell. So the mite knockdown needs to be well underway BEFORE that brood is being raised — which walks me back to strips going in early August, i.e. now-ish, not the 'after the summer honey, sometime in September' schedule half my local club still runs. Am I overthinking it, or is the club schedule genuinely a couple of weeks too late? And do people pull strips at 42 days or leave the full 8 weeks?