Miles: as for your "technical" questions (Chi Sao pressure, weight distribution...), i can't answer that, because my sifu doesn't talk and I don't ask - we believe that if you want to know something about somebody's teaching methods, you should go and ask that person. But, for info on LY, you might try these sites:
http://www.vingtsun.org.hk/
http://www.elywcimaa.com/

As for comparison between LY and WSL, my sifu always says that there's only one WCKF - the original one, but the people may differ. WSL was perhaps more famous, because he fought more. He thought Beimo was the most important test for WC practitioners, and, according to my sifu, his WC was simple, efficient, straight-forward and very much lethal . Lok Yiu, on the other hand, didn't fight that much, and isn't so "combat orientated". But they both received the same WC from Yip Man, and that's what's it all about.

From what I've heard, Lok Yiu doesn't advertize at all (very few HK masters do), and perhaps that's why he so "unknown".