twin headsails

I have two tracks in my headsail foil/furler. I have been talking to some folks re utilizing this ( two headsails set) as a down wind sailing configuration so well utilized by some boats.

I have also heard that some sailboats become quite unstable when rigged in this fashion. They need a gap between the sails to simply control the roll of the boat downwind. Any comments.

having the two head sails mounted in the furler would certainly be useful for furling of course as they would roll together. Might be useful for long downwind passages.