i think nonlethal Martial Art methods are useful.
i think Haito Tsuki (properly executed straight push with hand's inner edge) can be quite bold, strong and nonlethal. especially Jodan - aimed at opponent's face (around nose in this case, perhaps not only).
it seems that i can execute this move from all three guards i mentioned earlier fairly well.
mostly with right arm/hand, for now at least.
it can be combined with other moves, for example with wrapping other arm around opponent's waist to bring opponent down.
* what is inner many disagree, but from viewpoint of a Meditator, just put both hands on each other while sitting in a half-lotus meditative position, on your lap. then you'll know which part is inner.