Hi Jim,
I just finished making a similar set of cables last weekend. I had been eyeing John Risch's design for a while, but I could not source an appropriate length of 89259. I did, however, find another run of coax (RG11/U) with a 14awg solid-core copper center conductor, fluoropolymer foam insulation, and copper clad steel shield, so I decided to use it instead.
I did not want the steel shield as a conductor, so I removed it and wrapped the insulation and center conductor with an unwound alpha core, wrapped the whole thing in teflon tape and through a couple layers of tech-flex over each conductor. (this was a shit-ton of work!) It took me two nights to finish, but I am very pleased with how the cables turned out.
...have about 20 hrs on them now, and they are continuing to change with each listening session. It takes about an hour for the cables/system to warm up, and the music does some weird shit before they settle down. Once they do, they are very, very satisfying. It is too early for me to nail down their exact strengths in my system, but I have noticed more extension and authority in the lower frequencies, as well as more textural information (high mid-range?) in comparison to the TMC speaker cables that I was using before. (the TMC cables sound awesome for their pricepoint)
FWIW, I say use the belden and make a set of speaker cables. If you end up not liking them in your system, It wouldn't be hard to turn them over on ebay or audiogon and I'm sure you would get enough money for them to cover your parts and labor costs.
Matt
-here is some more info, if you hadn't already run acrossed it.
This site speaks very highly of John Risch's Design
http://www.tnt-audio.com/clinica/spkcbl_e.htmlHere is where I got the idea for the version that I built
http://www.aksaonline.com/discussion/discussion_papers_connect.html