I think a release agent is important, and I guess you are OK with grease, imagine if there were any potential chemical problem with grease the product would carry a warning. If you can’t reach everywhere with grease, the expensive spray-on stuff might do it as it is a fine mist, like CRC and would drift into those hard-to-reach places. Come to think of it, CRC might even be just as good. As with grease, first just make sure no chemical issues. Did you say you had a couple of test pots?
I am not too sure about the polyprop codline. Whether urethane would adhere to it or not, I don’t know – but depending on how you deployed the codline, beware of mechanical interlocking, that would give this stuff a pretty good grip.
Down here in the southern hemisphere, when there is nothing much else you can do, we say: "She'll be right!"
But better you check these matters out with David.