securing wire rope at right angles

[Brion Toss]

Hi,
You might want to serve the wires before seizing or clamping, in order to limit slip under load. As for the knot substitute when using wire, simply start with a long end, wrapped a couple of times around one wire, and trap that end under subsequent turns.
Having said that, I think you'll be able to generate at least as much friction and tension, with less flailing, if you use nylon twine over service. You can heave it tight, add layers, and frap it far more readily.
Fair leads,
Brion Toss