Here's my two cent worth of information on...
Ng Ying Kuen from a different perspective. First, I have to digress a little.
White Crane, Pak Hoc, is well-known and has been around for quite a while. Wong, Yan-Lum (WYL) was a contempary of Wong, Kay-Ying and Wong, Fei-Hung. The were all acquaitences and members of Kwangtung's Sup Fu (Canton's Ten Tigers). It is even rumored that WYL has some influence on Wong, Fei-Hung's Fu Hok Sheon Ying Form (The upper/downward cuts and "pow" upward swings). Interesting rumor that has been floating around for decades, but just that - a rumor to note. The execution of these hung gar techniques and white crane's "pow (upper cut) and cup (downward cut)" is different in taste and form. But who knows...dang...I am going off on a tangent again. Back to the subject of Ng Ying Kuen!
White Crane kicked a lot (really...a lot) of ass in the old days in Canton. They took a lot of challenges on platforms and to this day, remain elite and difficult to cull any significant amount of information on their style. They have their own organization (social, political, and martial arts wise). They do not care to associate with other system; hence, we do not see a lot of intermediate or advance sets demo'd to outsiders. Snotty behavior, but they possessed a very effective and efficient (no block but strike)system.
As was the tradition, if one came across a superior opponent and lost the fight then you would join that style. White Crane acquired a lot of different martial artists(MA) within their system. For example, Luk, Ah-Choy who is Quentin Fong's sifu was a traditional Choy Lay Fut practitioner and they have some CLF influenced flavor in some of their white crane forms.
Many of these MA still practised and retained some of their old forms. By the time Ng, Siu-Chung (considered the Father of White Crane) standardized Tibetan Lamma into White Crane during the WWII period; Ng Ying Kuen was already in the pak hoc system. A hung kuen practitioner (don't know who he was) had brought in Ng Ying Kuen because that was the set that Hung Kuen practitioners were taught and prevalent at that time and NOT Sup Ying Kuen. This is white crane history.
So if you ever luck out and see a white crane demonstration of Ng Ying Kuen, please note that it IS a Hung Kuen Set. Even the white crane clan say that it was from a former Hung Kuen MA who joined their lama system. The form has some interesting dynamic tension that we associate with hung gar and even has the signature "que sao (one-index finger)" coupled w/sei ping ma AND yee gee kim ma. The crane is done in dynamic tension form also...very, very interesting indeed.
I thought that Paul and DL would find this though provoking...heh, heh.... So there is some oral history from the white crane clan supporting the Ng Ying Kuen stance as a major form at that point in time, back in China... Remember that it is just my two-cents soooo please do not get agitated if you do not agree.
Sorry, sorry, sorry...a correction!
The teacher of Quentin Fong is Luk, Chi-Fu and NOT Luk, Ah-Choy. Sorry for that late night error!
Having talked to my sisuk, it is a mistake to assume that all hung kuen practitioners from the "Kwangtung Sup Ying" period learned everything. Even as late as the early sixties, some hung kuen people never went beyond Fu Hok Sheon Ying Set. He mentioned that the mentality was not to collect and learn all the sets, but to work on what was taught to you and explore and excel in your form, martial arts skills until you were **** good. If you opened up your own studio, and your students wanted to learn more, you would just send them to one of your sihings or sidyes or the form/training. No big deal...