When Chow Bak Tung first shows up in LOCH, he is not yet quite on par with the Greats. Chow consistently lost his fights against East Heretic Wong Yerk See on Peach Blossom Island, though they were generally closely contested skirmishes in which Old Heretic had to put serious effort into winning.
How soon did Chow Bak Tung make up that small gap between himself and the Greats, and was it primarily due to some improvements he picked up unconsciously when he read the portion of the 9 Yum Jen Ging from Chan Yeun Fung's skin?