The use of double knotting is interesting, as it does seem to be a succession to the chain wiring on earlier necklaces. By the 60s and 70s, holes in cloisonne beads had been diminished severely from the giant holes in the 1920s-40s, but they're still much larger than, for example, pearl holes. So if one isn't using wire links, then fabric cord has to accommodate different hole sizes - a knot that won't slip through a gemstone bead will slip right through a cloisonne bead. Thus double knotting.

And there's a trick to tying the double knot exactly where you want it, tight alongside the bead. The usual instructions simply go along the lines of "do two overhand loops and pull from both ends," but that doesn't work for precise placement. Hence the twist-and-flip method that takes a bit of practice, same as pearl knotting.

There also seems to be a progression in silver filigree clasps, that I'm still collecting examples of. Earlier? clasps on the better necklaces are well made, then deteriorating to the sloppy and cheap plated clasps of the 80s and 90s - fitting accompaniments to the sloppy cloisonne beads from these same decades.