Solveig-san --- and everyone --- I don't have a copy of it any longer,
but I believe my article in the Second Tyr Yskithyr Heraldry Symposium
could offer some background on how mon were registered. As I recall,
we were at the time fighting out whether monshogaku was in fact a form
of heraldry at all, and I researched the existence of formal
associations as part of that.
Of course, it having been roughly 30 years, I may misremember.
You would find it under my secular name, Yamaguchi Yukio.