I second what Kim said. I just went through that when my forms were set and then the gunite. I had made quite a few changes - enough to drive the designer batty. She did her best to keep up with me, but some of the updates didn't make it to the PB or the gunite company. I gave them my current plan in a sheet protector (it was always raining or at least sprinkling).
I also gave them my inspiration photos in plastic giving finished details of how our steps and bump out bench should look since they were a bit unique. Still, some small things turned out differently than expected, but I would have had to stand right by the crews to oversee. I just couldn't manage that. All in all, I'm getting what I wanted. But have plenty of photos in plastic (even if it isn't raining, the crews' hands are often gritty or muddy). The crews seemed to really appreciate the photos, they often were huddled around looking at them.
Man, what I have learned so far from this site and from experience - it's amazing!!! I envy you young ones who may get to build another pool someday! Good old 20-20 hindsight. Take care! Suz.