Smaller hammocks. My cage is 1ft across and I just hang it from one side to the other. Though I am more of a fan of pocket ones so they get a little more vertical space and they can't roll off the sides since I have to make them a little more narrow. I do HAVE to make my own though and can't buy the ones in pet stores as they're way to big.
If I make a hammock to big for the cage then I just hang the corners closer together and it naturally makes more of a pocket anyways.