Just a heads up: Wax isn't wax, if it has the wrong properties you could get anything from sub-par results to a complete mess. Most commercial waxes are a paraffin and bees wax mixture, vegan discussions about honey aside if you're really up for it you can try and find an abandoned hive in the forest. Another, not exactly inexpensive but very good alternative is microcrystalline wax. Not that beeswax is inexpensive either, though.

I happen to live in an area where it rains a lot, but most of it isn't drenching, plain moleskin (that's cotton, not mole leather) is sufficient 99.9% of the time and the rest, well, I get drenched. I'm not hiking out in the wilderness so it's not exactly a survival issue. Though the only reason that moleskin is sufficient is because it's multi-layered in the areas that count, especially shoulders and upper back: The upper layer can get drenched while the lower layer stays dry enough. Also moleskin is so dense it needs flaps for comfort: The lower layer has slits for that reason, covered by the upper layer which is open at the bottom.