For the record: I haven't seen/felt much myself with regards to fajin, but I'm curious what makes you so sure it's impossible to pull off a fajin with the dantien to mingmen against even a decent high school wrestler. If you'd say that it would just take to much effort to get a decent fajin with the dantien to mingmen to be worthit, that would be something else, btw.
it might be a wrong assumption, but i'll offer this anyway;
i think what Dan might be talking about is what we call "splitting force", where even though we consider the ming men to be the main yang point, and in the beginning we put a lot of stress on feeling the x from the ming men to the hands and fee and feeling that during projection, later on you learn to develop "splitting force" where you can choose any point on the body (usually the point of contact or somewhere close) and explode from there, using that point as the "base" rather than the ground itself. it's faster and doesn't telegraph.