[Refplace]

You could still have the check digit with 3d6, just roll 4d6 so you get the bell curve but still keep that crit aspect as a side thing.
And Wiliam has it right there is a lot of opportunity on the W23 wishlist for a creative author. A GIN topic could slide into Monster Hunters or Cabal, much less IW, IOU or Illuminati.
The book needs be good enough to sell, but does not have to fit perfectly into the GIN or IN cannon, especially as in not requiring those books to use it.
The goal is to sell more books and for this topic to increase IN visibility.
A MH adventure (or series of them) that hinted at IN and used some of its plots could rekindle that interest.