I was thinking the same thing it might get confusing trying to pick colors. Would it be better to just list 18 colors and you pick that group, but then you do come up with the problem like AWM said if she is buying hers local. I will be ordering mine online. Also, I did this kind of swap a few years ago, and we printed the color and texture on address labels and stuck them to the non textured side. It would make them look better, just my opinion. 
