We are trying to figure this one out too...
Two years ago it was suggested to use bottom paint so we painted our bronze prop with the same ablative bottom paint we use on the hull. (CSC Micron, which as an aside has performed very well on the hull, with two years between haulouts we came out clean.)
There was growth on the prop within two weeks....(we can see our prop with no trouble). When we hauled most recently the paint surface was all pitted and the prop had lots of barnacles..... It took a really long time to clean it off the prop and get a smooth surface. Never again will I put bottom paint on the prop!
So this time we are trying plain lanolin, Lanocote has made a product from lanolin for bottom application, but we just purchased a tub of lanolin at the pharmacy.
So far so good, at 6 weeks the prop has no growth and even if it does not work out in the end, we can just wipe any remaining lanolin off at our next haulout, at least thats the theory.