Are case humidifiers good enough? I decided to find out for myself. Reluctantly, I drilled holes in one of my Taylor cases, so I could feed hygrometer leads inside with probes placed at various positions in the sound hole and around my guitar. The goal was to allow the case to close tightly, without pinching the leads or having the case cracked partially open.
I placed my 414CE, that I normally maintain at 45 to 50% relative humidity inside a Musik Tent, into the case and inserted a wetted, dampit style, humidifier inside the soundhole. Next, I placed hygrometer probes in the headstock area (1), near the neck/body (2), inside the soundhole (3), and on top of the body near the strap button/output jack(4). I placed a another probe outside as a reference. I then latched the case shut and left this setup to stabilize overnight.