Has anyone tried making a hammock that was a little bit shorter in the middle than it is on the edges. Like a concave cat cut at the head and foot ends of the hammock. I was laying in bed thinking that maybe a hammock that had slightly less fabric in the middle might pick up my rear end a little bit. and having slightly more fabric along the sides might make it easier to get flat if you are laying diagonally. Not sure if that is making sense. If so ... has it been done?