Hey Ryan - thanks for reaching out. Happy to help with some tips. The cable we used in this photo is Feeney Cable Rail http://www.feeneyinc.com/Architectural/CableRail-Standard-Assemblies   You can find Feeney at lumber stores like Truitt and White in Berkeley, CA (if you're in the area) - and I think even big box stores have started carrying it. Check their website for thorough installation instructions.

I think the post spacing here is about 4' on center. Make sure to make your post holes deep enough - 2' - 3' - because tightening the cable can torque your posts. We used 4x4 redwood posts for this application.

Please keep in mind that this is more of a trellis for grape vines than a guardrail. If you are installing a guardrail, you need to make sure the cables are less than 4" apart.

Hope this helps - good luck with your project!

Pam