I have had weather stations installed for over 20 years. About 8 with Davis and the balance with a Dallas Semiconductor station. (no longer available, but used TxWx mechanicals).
My experience has been the the "natural" nylon tie-wraps are indeed susceptible to drying up and cracking in UV after a few years. They get quite brittle and I have had them fall apart on me.
On the other hand, the black "UV resistant" ones have never given me any problems and have been up for years without a problem.
Where I live in Michigan isn't a high UV location and I know that in the high desert in the SouthWest, the UV is brutal.
The only caution I would have about clamps is the possibility of the fairly sharp edges cutting into the cable, especially if the wind catches it and begins moving the cable against the worm clamp steel edges. I think that I have seen some rubber covered clamps, but this might get you right back into the UV issue.
I would wrap the cable with good electrical tape in the areas that will have the clamp to protect against this possibility.
Greg H.