I've noticed that kind of difference in terminology. What some CMA people call a "set", I would call a "sequence", which when combined with several others makes up a "form". But then you've also got Xingyi with certain animal "forms" that in terms of length barely exceed what I'd call a "sequence"..
Yeah... it is kinda special.
Normally in my circle of experiences, we use "set" as the term for a complete handset. A "sequence" would be a "line". A series of lines until a direction change, a "road". Multiple roads, a set. A "form" to me (again just me) is a posture or movement. "The form" would be an "aka" for handset.
Going back to the Tiger Swallow thing, can anyone tell me whether there is a "large" (or even a "medium") Tiger or Tiger/Swallow form in Tanglang or any of the other northern styles? I assume that if there's a "small" one, there must be a larger one too.
No idea. I'm not familiar enough with PM to keep track of the sets outside of the major known & popular ones.