The head in Jabberwocky, our Freedom 28, had one and it was great for light and ventilation.
Saw one pictured in Yves Feder’s Sabre 34 and realized it could work in our boat. The #00 size doesn’t often show up in listings, but it’s for real. Interior trim covers the opening and holds the screen. Set a Sun Shower bag on the deck and you can shower inside.
The photo above is from testing for position; as installed it opens to port. Amazingly, other than the horror of cuttting a large hole in the deck, it was a straightforward project.