We would like to install fiber optic lighting in grotto, like in your youtube video “Using Fiber Optic Lighting in a Grotto” The question is How do you install the strands? Pre- or post-gunite? If pre-gunite, how to spray gunite without damaging the fiber strands? Also, do you need to protect the strands with some sort of tubing? If post-gunite, how do you install and hide the individual fiber strands?