Securing 1/2" pvc inside dry rock?

[lastlight]

So do you guys think this would work then using just zipties?

I'm thinking in my base rock I drill 2 small holes maybe 6 inches apart all the way through. Then I drill a matching pair in the rock to go on top of it. Then use super long zip ties or use them in series so that I end up with one zipped up string going through both rocks in a single loop?

Will the UV black ties last? Even if they're going to break in a few years that's not ok and I'll use pvc and epoxy.