Firstly, there are others here that can speak to the A/C issue more knowledgably than I. My comment was based on the fact that you have a relatively large enclosure, the surfaces of which will become quite cold from the chilled air. Theoretically, most of the moisture in the air passing through should have already been condensed out on the evaporator plates as air is blown through the system. Never-the-less, as the compressor
cycles on-and-off some moist air will makes its way into the space--particularly in Marathon where the humidity can be pretty terrific. That air, hitting the chilled surfaces on the inside of the bulkhead "plenum", could give rise to condensate. On our boat we have teak
wedge diffusers and I often find these and the adjoining woodwork to become somewhat moist from condensate. You have a larger area that I suspect may be somewhat more difficult to access, hense my observation. You have a nice looking installation
and it was a creative approach to distributing the cooled air. Hopefully it will be problem free.