I hear what you're saying, Deep Blue, but I think if you're going to translate/edit a work into English, you need to do so primarily with native English speakers in mind. Otherwise, you end up cutting yourself off from a huge swath of idiom and poetics just because the non-native speaker might not have been exposed to them. The resulting prose would be functional yet totally flavorless.
Anyway, I don't think I'd call the entirely of the native English-speaking world "a very narrow audience." This particular slang usage of "pearl necklace" can be found in the U.S., Canada, the U.K., and Australia. I don't know about New Zealand, but I'd have to imagine that if the Aussies are on board, then so are the Kiwis.
All that said, I honestly feel bad that non-native speakers like yourself might be (literally) left out on the joke. So you have my apologies for that. If you ever find yourself in New York, I'll buy you a beer as a make-good.