the manual says to the bottom, so thats pretty much the best answer your going to get. i personally put them to the bottom on mine and any that i pack as well. i remember a while back there was a few ideas for putting them with the lines up. ive heard a few reasons why, but mostly it was because it fits the shape better (fatter in the middle skinnier at the bottom.) personally ive closed it both ways and it looks exactly the same, and packs the same both ways.