So I'm trying to string some polys up on my Gamma Progression 200. I can string any other string other than poly. I feel like I can't string it, and that my clamps won't hold tension and I've cleaned them, and set them tight enough just so it won't damage the strings. But I feel like it's impossible to string, especially since the Progression 200's grippers are nothing more than sandpaper. What do I do?