I'm not interested in anything fancy, just a simple berth for changing, getting out of the sun, and the occasional overnight.

My 06 28 daytona has a nice queen berth with facing dual love seats.
Very roomy considering it's a 28' cat.
A friends 27 does not have enough room under to change or sit up- only lay down....just a pad

Yes the 28 is much more roomier, but the bed in the 27 is larger, my wife and I spend about 10 nights a year on our 27, but due to the low deck you don’t get much more then side action down there. There is room to change or even apply pasties. The 25 has the same coolers mounted in the floor like the 27, but the bed is smaller more like a twin or a little bigger. I went from a 30' scarab and it is much easier to sleep on a rectangle in a cat rather than a triangle in a V bottom.

I would nt go anything smaller than a 28 daytona tall deck for the occasional overniter. And speaking from experience you dont have to worry about the side to side action. Although not huge there is enough room to take care of business on top

My cabin is decent my wife will not over nite?It's always good to have even just for storage!