I'm in the planning stages as well being an avid woodworker and newbie cigar smoker. I haven't found a single good, all inclusive reference on humidor building.

A good cabinetry or jewelry box book will probably be most helpful. Otherwise just seal the outer box before you put in the spanish cedar. Have the cedar stick up about 1/4" around the edge of the box and recess that much into the lid. This is how most desktop humis create a "seal".

I'm not sure about a cabinet humi though, but a cabinetry book will probably have some good ideas.

Good luck and have fun. Keep us updated on the progress.

spiffy