Has anyone bought any of these cable necklets- catalogue page 418?

Just wondered what they were like. I want to make some cluster like button necklets in this kind of style but with buttons and not sure what kind of necklace/necklet to buy.

I just just want something very simple/plain to put all the wired buttons onto so thought that maybe on of these necklets would be good, but wonder what they' be like with weight on them - do they stay circular or loose the circular form when they've got weight on them.

I was also looking at the plain neckwire with tube clasp - catalogue page 417.

Or maybe I should go for a chain type of wire and hook the wired buttons into the eyes of the chain. IF so what size do I get. I'm new to necklaces and have no idea!!!