For saving weight another tack might be to cut one of the aluminum rings in half. Looking at how far up the cord "rides" up on a ring, it strikes me that theres no real danger on a 2" diameter or greater ring of it jumping off. One of these "sling rings" (sold here as "aluminum suspension rings") would do.
Of course, cutting a ring to save maybe 10 grams by using 1 instead of 2 is something only a gram-weenie would do.
The half ring is how I arrived at the S-bar idea; I was thinking if you had half a ring it could work but could also slip out of place when not loaded. A ring is probably also stronger than an S or a half ring at resisting being twisted out of shape because its ends meet across from where the cord wraps, reinforcing it, so you could probably get away with a ring made of thinner stock than you could with another shape.
And yes, at a certain point, it becomes design for design's sake