[shilala]

I also use a wetted sponge on a plate or tray. It provides FAR more surface area than a bowl of water, and it gets the job done very well, in a timely fashion.
Spanish Cedar is a very open grain and sucks up water very quickly. Thing is, most humidors use a spanish cedar laminate that is paper thin or thinner. The backing wood is usually some sort of composite, and composite is designed to repel water.
In reality, you have very little wood in a humidor that will absorb water. The trays and wooden pieces inside the humi are what's going to hold your water.

Mind ya, I'm speaking on the types of humidors that we can buy at major retailers and the like, not handcrafted humidors.