I have one in the exposure unit right now from the set that I floated. The good news is the edges went dark after a minute and there is image 12 min. into the exposure (using a UV box), so it is working at least a little. The bad news is the coating is splotchy as all get out, and the edges are not as black as I remember POP being with no film base to blast through. It has the nice eggplant color though.
I am coating on the gelatin side, not the back, because I wanted a glossy print like POP was. There was a salt print on old fixed out silver gelatin paper (or two) by Emmet Gowin at the Princeton Museum that ended last week, and that is what got me going on this little kick. So I know it can be done. How long it will take me to do it well is another issue altogether.
I just finished salting by immersion six sheets I rubber cemented back to back. Those are drying now, and I will sensitize as soon as they are done to see if they end up being better.
Ian, that is a good point about the salt not getting very deep into the gelatin layer. I will try to mix some gelatin into the next mix of salt to see if that helps.