I mispoke before - the already look neat and hemmed, I just mean it may look neater if they are hemmed to the exact length of the window, so the curtains end on the window ledge (or maybe they already do that? long windows!).
Cat Cable, hah! Poor kitties! I suppose you could open them when you don't need privacy
In short, I do think it would look good hemmed to the length of the white shelf