Built this this summer. It looks better now. 26'wide by 30'deep with 10'wide by 12' high doors. (Chubby towers are tall)
I've never seen anyone complain about too much space in a garage. Or seen a real one that was too empty. I can hang the catamaran from the ceiling above a boat if I want to.
Power plugs in the ceiling let you get tools, vacuum, or a charger in without draping over the boat. Lots of light is also important.
It's on a bit of a hill.