Only things I'd do differently is spin one of the boxes around so the air has to go to the far end to get out rather than staying close to that front wall. Your baffle will help some there, but I think it would be a better design if you turned one opposite.
The second thing I would do is use a hygrometer that records highs/lows for a 24 hour period. The extremes are what you are interested in, especially those in the middle of the night when they're highest.
The second thing I would do is use a hygrometer that records highs/lows for a 24 hour period. The extremes are what you are interested in, especially those in the middle of the night when they're highest.