In mast furling
I've been sailing my B361 with in mast furling for two years a wouldn't be without some type of mainsail furling. If it's a good idea for the headsail, it's good for the mainsail for the same reasons. Just makes life easier and sailing more enjoyable. No, it doesn't perform like a battened sail, but if you really learn how to set it, you'll really enjoy using it.