Namaste..
Though it's not for HeroQuest, there is a nice write-up of the
Korgatsu/Hsunchen tradition for MRQ in "Cults of Glorantha II". I've been
acquiring the PDF's online on Drivethrurpg.com. It includes some rules on
Integration of Spirits, but MRQ's mechanistic emphasis on POW/MP/Combat
Rounds doesn't jive that well with HeroQuest. That can be fixed fairly
easy, however, by a good narrator.
-Santo