This is what I would do if you had air conditioned home. Plug drain hole, slap some boveda packs in it, leave un-plugged, and keep it out of the sun. I have a 16 bottle wine cooler with about 10 boveda 65 packs. It holds 5 cedar trays, and 3 boxes of cigars. It stays un-plugged in a closet and sits rock solid at 65/65. It has been rock solid for 6 months and boveda packs feel as good as day 1. In terms of the metal shelves, I would pull them out and use old cedar cigar boxes as shelf material.

Good luck!