[jumpinjeff]

I have 4 Acurite digital hygrometers. I have them in rooms where the guitarsenals are stored and where I do a lot of playing. I also have one outside for curiosity sake. 48% is the happiest place for guitars and always what I shoot for if I am drying out or humidifying when the ambient humidity gets out of whack. Today it was perfect inside and out. No effort needed. And whether it is a coincidence or not the day actually has been exceptional so far.

You sound like you were going for precise measurements. I am too lazy for that precision. These digital ones are close enough for wood preservation.