Look at ( Rush river website ) 406 lines for cane & glass fly rods.I am familiar with silk lines and their ability to cut through the wind, but I've never thought they enable you to use a lighter line for any given rod; a five weight is (or ought to be) the same weight whether silk or plastic. Like you, most of my fishing is done inside 15 yards - in fact most of the time it is inside ten, including the combined length of the rod and leader, so I often only have five yards or so of fly line beyond the rod tip. If necessary I'll go up a line weight rather than down, to load the rod sooner.
Evidently from the photo the line works for you, which probably just means you're a better caster than I am. I must admit I struggle with light lines, even on rods well-suited to them.