[jseth]

I use both a soundhole devices (Planet Waves and Damp-It) that slip between the strings, as well as a shallow plastic container (cream cheese? Guacamole?) with a chunk of sponge in it up in the headstock area. Never had any issues, and truthfully, don't have to use the soundhole one very often on the West Coast...

NO... if you put the dish in your string pocket inside the case, it won't do much if anything for the humidity of the guitar neck and headstock... however, that string compartment will be nice and moist!

Just use common sense and you'll be fine... a great rule of thumb to follow is: If YOU are uncomfortable with the weather/humidity, then your GUITAR is probably uncomfortable, too... and, as Larry said, "close" is plenty good enough; good enough for his Olsen, good enough for my custom Goodall...