If I were to put one in, I wouldn't put in a small glass one like in the pix above, but rather a large foldable sort. Typically that would be much wider and longer, about four to six times more opening area. These were often an option for many new cars of different makes.
WEBASTO used to make those until very recently. A pity they don't make them any more!
On cars with a brace in the roof like ours, that sort could routinely be installed, because that style roof has its own frame.