We virtually had no moisture accumulation in the v-birth other than a little underneath the memory foam mattresses; was going to put some of that Marine bedding mess underneath the mattresses but never got around to it.
The Wallace recommended an inside & outside air return. My idea with putting the inside air return all the way forward what's to draw air from the cabin up into the V birth, and it worked well enough.
The Flex Form was easy to install because it's stretched in both directions you just need to use the highest number spray adhesive you can find, spray booth Services wait for about 30 seconds and then just put it in place and press. I purchased through an upholstery shop locally not sure where he acquired it.
If I were able to convince the wife I would have placed it on the roof of the cabin I think it would quiet things down quite a bit when underway and of course add an insulating quality
By far the Delt T spray insulation was the bomb, on the 22 I sprayed it in the v-birth and the cabin, you could practically talk with a whisper when underway Plus moisture was eliminated totally amazing stuff. I applied a good latex semi-gloss over the whole thing. But man that was a lot of work masking everything off and spraying on multiple codes and it wasn't cheap.