If the wood was properly dried, there is absolutely no need to let it "acclimatise" before you start working it. You can work it immediately. I would, however, let it come to your local EMC ("acclimatise") for at least several days before you start tillering it. But I assume that'll take at least a week anyway, so that is no problem. Once you have her floor tillered, it will have had enough time to get to EMC.
Calculate your local EMC based on average temperature and humidity. Don't rely on a wood moisture meter. In my climate, I must not store wood in a bathroom, as that will elevate the EMC too much, above the optimal moisture content for most woods. However, if you live in a dry and hot desert, your EMC might be too low for yew (but optimal for hickory) in your loving room. In that case, a cooler and/or more humid room such as the bathroom is a good way to raise the moisture content of the wood. But you need to make sure that it is needed, since that depends on your local climate.
That knot looks a bit dangerous, with that dead wood and bark remnants around it. Where is it located? In the middle of the stave length wise? And where is it width wise; how much healthy wood do you have on the other side of the knot?
