We could spread the word in the comment sections of low-viewed music videos and songs over on Youtube--specifically the genres of breakcore,incelcore and newer shoegaze stuff. A lot of these communities seem like they would have an affinity for Heyuri Culture--these videos use a lot of oekaki-like anime images and the fans have a lot of crazy humour.I've even seen some pretty good OC images. Of course a lot of these potential newcomers will have to be weaned off of nu-chan culture,which is what rule 8 is for.
I emphasize songs with low views, (under 10,000 maybe),because if only a select group hears about Heyuri, it'll reduce the amount of annoying and weird people coming round.