I like the bolts-through-springs approach but it would be better still if there were spacer tubes so the springs can't touch the threads. In short, 4-40 bolt inside a 3/4" spacer; spring around that; bracket around spacer engaging spring. I haven't been able to find a similar bracket with a large enough drill hole but drilling them out isn't hard.
It is starting to become clear that there are important physical differences between link-type treads and big rubber bands with holes in them. They are not the only elegance/money tradeoff, however.