I have been intrigued by this subject also.
It is obvious, even to a complete novice like myself, that there are two basic categories of these postures.
Firstly, and most obviously, are the symmetrical postures, (symmetrical in that both arm positions ideally mirror one another), and these positions are based around the etheric or electromagnetic field (of a spherical nature) whether in an opening or closing aspect (i.e. hands facing towards or away from the body).
The other category concerns asymmetrical positions of the arms and hands, the most clear examples of which I have encountered in the bagua mastery program. I cannot comment on these as they are advanced postures and concern all sorts of freaky things happening within the energy field; differences between the opening and closing of the left and right and all sorts of freaky energetic connections and flows and whatever…
There is, in my most humble opinion anyway, no need to worry about what the whole 200 postures in detail, because you would be wasting your time and distracting your mind from the immediate task of mastering some very basic aspects of the most basic postures, which is far more important.
Just a very basic view from a very basic beginner, I hope you don’t mind…