Yeah one of the guys who posts a ton at that hot sauce forum uses the cabbage leaves to top all his ferments. He doesnt put anything on top of the cabbage leaves, just adds a packet or two of Culturelle probiotics to really kickstart the ferment. His theory (as far as i understandi it) is that if he gets the ferment kicked into high gear as fast as possible, the C02 that is released pushes the oxygen out thru the airlock before the mold can set in on the cabbage. And once the oxygen is gone, mold cant grow.
Of course he lost two jars of fermenting mash just as i was gearing up for this attempt. He claims its the first time he’s ever lost jars to mold, and he says he’s done like 40 batches. It kind of freaked me out, so i didnt put thecabbage leaves on top. So far, it seems to be doing ok.