I compared Kim's material with Liang Shou-Yu's and whilst both do leave out certain (key) information, there are many similarities in the finger knitting methods and some glaring differences. There were also some "discrepancies" in Kim's manual, but without further research it is difficult to ascertain any sort of accuracy unequivocally. In any case, Kim's manual certainly uses the right "lingo".
This is one of the difficulties I face in my research, because the teaching is traditionally closely guarded, and those in the know, are unwilling to share the investment in time and effort, for various reasons - which are understandable.
The other difficulties I face, is that hand seals are only a small part of a larger body of related knowledge that also include body seals, mantra (sounds), breath, visualization, and meridian/channels (among other things). So, invariably my research at the moment tends to be broad rather than deep as I would like it.