Although this has been posted before, here are the rules of Humakti duels as presented in the forthcoming Cults Book:
The nature of the Code of Humakt is such that arguments, discussions, or any sort of disagreement can be settled by a (hopefully) non-fatal duel. The cult strongly encourages such duels. The rules for these duels are few and simple:
Both duelists must be at least lay members of Humakt. Thus, all involved parties know that the Honor Passion will be foremost.
The fight is to the first fallen. After one combatant drops to the ground (e.g., through incapacitation or unconsciousness) or drops their weapon, the duel is over.
Any Rune or spirit magic is allowed except Sever Spirit. The use of allied spirits is allowed, but not that of bound spirits or other companions.
The loser must pay some reward to the victor, as agreed upon beforehand.
In many tribes and war bands, most warriors become lay members of Humakt as a matter of course.
So for example, the White Bull party includes an initiate of Orlanth Adventurous, Orlanth Thunderous, Storm Bull, and Ty Kora Tek, as well as an initiate of Humakt. But they are all lay members of Humakt.
it is no difficulty for a Yelmalio initiate to be a lay member of Humakt, and in Dragon Pass I suspect many are.