Addressing some concerns:
Weight: There is a big difference between using 1/16" and 1/8" shock cord. Remember that doubling the diameter roughly quadruples the weight (theoretically). The thin stuff weighs very very little, even when you include 40 ft of it. I'm using a simple 10 cent key ring which also weighs virtually nothing. In exchange, i'm dumping the 1/8" shock cord normally used all around, the secondary suspension cord and hardware (if any), and the cinch-ends. I have not directly weighed them all (can't be bothered!) but i can feel the difference in my personal setup. I'm all in on clews. If you take measurements, please let us know what you end up with.
End Gaps: In the image i posted, there appear to be some end gaps. Keep in mind that i'm not actually in the hammock pictured. The quilt spreads out flat when you climb in. Also: more nettles would spread out the distribution of force. Mine has only 8, which is what i'm considering minimal. Also also: I fluffed most of the down towards the bottom/center, so the ends don't have much left to fluff up with in the picture.
Stretchy Fabric: This is something i had also considered, but didn't know what fabric to use. I think its a great idea, as it would produce a perfectly graduated distribution of force, just like the hammock itself. One concern is that it may not adapt well to a larger-than-built-for hammock.
Nettle Length Issues: Remember that you have force pulling on both ends and they tend to even each other out. Even if you don't get the exact distribution you expected, you probably won't notice. You still get uplift and hug no matter what. This is a non-issue. However, of course you should test it at home before heading out on a winter trip. For what it's worth, i'm using nettles of all the same length (mostly to avoid building a special jig for it)