I usually buy walmart out of all of their large damp rid pales and put them in the cuddy. Better than nothing. i dont shrink wrap my boat, but it sits in storage with cover on and all the doors shut. This year, i took the cushions out to allow it to air out a bit more.

1 large one is good. I put one in cabin and 1 in engine bay.

This (larger one) is exactly what I use in my 26ft boat under the canvas.

Fair warning though... it keeps the interior and canvas warm and dry... which is a stray cat magnet.

Before building my garage, I always had neighborhood cats on top of my boat during Winter months. It drove me crazy from all the cat hair on black canvas.

I have always used the damprid buckets when wrapping my boats. Never had a single moisture issue. The buckets always had about 1" of water collected in them by spring time.