My 2120 is shrink wrapped and I always keep the door, hatch, and windows closed. Reason being that the opening by the outboard engine well along with 4 vents in the shrink wrap allows for good ventilation throughout the boat, including the cabin due to the permanent openings under the cockpit steps that allow good ventilation into the cabin. This keeps the cabin dry even when there are large temperature swings that sometimes cause condensation on the underside of the shrink wrap. When condensation does occur, it dries out within a few days as the temperature gradually stabilizes.
I always found the cabin to stay dry this way.