So I was doing some research, and I came across a recipe from Valrhona that called for the PDF to be piped into a bonbon. The recipe called for the PDF to be cooked and set, then put in a food processor with some Absolu Cristal, a glaze made by Valrhona. The ingredients for Absolu Cristal are listed as water, sugar, glucose syrup, pectin, carageenan and citric acid.
I wonder if you could just add a little corn syrup (and maybe a little bit of water) to the PDF to get a similar same effect. You get a liquifier without adding much water and should have little effect on shelf life.
(and BTW Jim, I have seen in other posts by Kate that she generally does clean the excess cocoa butter from the molds before filling them).