Our PB never goes below.
1. We store it lashed to the side of the main cabin when heading out for more than a day trip.
2. It sits on the side deck for day trips if the weather is questionable.
3. And tows nicely in fine weather.

The seats and transom both fit nicely in our aft cabin for number 1 and 2. For number 3, the transom and seats fit nicely between the PB and cabin sides.

I built and used a nesting dink and it did NOT work for us. The only place to store it was forward and it covered our forward hatch (the only way out of the cabin other than the main opening).

Just a bit more info. By the way, after our PB was past the "new" stage and was easier to open and close, we can always set up and take down faster then any deflatable we have seen or cruised in company with. Not critical, but I always made it to the fishing spot first.

Greg