I have since gotten a Lockdown Silica Gel Can, 750g as well as a digital hygrometer. Here are the results:
Baseline: our house's humidity is normally 51% (we live in Southern California but we are in a coastal area). Our heater has a humidifier and when it is active, humidity rises to 64% in my camera closet.
With the humidity at 64%, I placed the Lockdown silica gel can in the closet this morning. By the time I got home, the humidity was 37%. (Note that my camera closet is not completely air tight. It's just a regular closet.)
Based on these results, I think the Lockdown silica gel can or a similar product would be the best solution. I don't need the air tight container or the smaller desiccants.
UPDATE: I have since opened and closed the camera closet several times. Each time I checked, the humidity was at 37%. This is close to the supposed ideal of 40% for lenses. I have not tested this product in other environments (more humid or less humid than our house).
2/13/13 UPDATE: The past couple of days the humidity at our house has risen to 70%. The humidity in the closet with the silica gel can went up to 45%. (The recommended range for lenses is 40% to 50%.)