There's a pretty simple optimization in the labels you can do, but it doesn't really help that much. The first block of letters is XORing with one set of prime

There's a pretty simple optimization in the labels you can do, but it doesn't really help that much. The first block of letters is XORing with one set of primes that follow a common pattern, but the second one is stumping me. I let it run overnight and basically made no progress once it hit the second block.