Humidification

I was wondering if there are any further tips on humidifying both an acoustic and electric guitar respectfully. I've come to figure out that you need to get a hygrometer/thermometer first, one that shows present humidity/temperature as well as past humidity/temperature readings. The problem that rises is that hygrometers aren't always that accurate, so you have to include the possibility that they are off by as much as 10%/degrees. That being said, I think preconditioning both guitars with subtle humidification devices is the way I would go about it. Weather plays a big part, in the dryer the region the more you need humidity, whereas the wetter the region the less humidity you need. As far as specific humidity devices, tap water products might be more subtle than water vapor products. Water vapor products might be cleaner than tap water products. If for some reason you can no longer humidify your guitars you should try to ween off at a time when the humidity/temperature is most desirable. I'm still trying to find a subtle humidifier, Herco makes a versatile clay-like one but I wonder if it's not subtle enough. Sponge based ones may be more subtle but don't last as long as a Herco. Any suggestions?