That seems counter-productive. I would be surprised if the PC sticks well. When spraying autmotive paint, any trace of silicone will result in fish-eyes" in the finish (just what tomme says). I would personally not want that around....it is interesting the PC stuck at all....maybe the heat does something to it??? Silicone matts seems to take heat well, so I don't think that is it. Paint (latex, in the home)won't stick to silicone caulk. Wonder if anyone tried this and shot them.
I also don't shake, it just breaks my containers, #5s seem to be brittle. Swirl for 30 seconds or so....won't PC with humidity over 50%, I just wait for a drier day. On Amazon you can get little digital meters, I got a 4-pak for under $10 I believe. I use Smoke's PC, he double bags it and I keep those bags in another large sealed freezer zip-lock bag. As they say, "keep your powder dry", that apply here too! Good luck, keep trying!