Although that new sword drill I posted the other day is the last & best word for Ba Gua energy training, if you ask me what's the best #1 Hit overall, beyond any doubt the greatest and ultimate energy work is what I call ZZP ('zip') drill, Zhang Zhuang Pinned. Of course nobody ever mentions or raves about that, simply because nobody understands it yet. But I don't blame the victim. If people aren't raving about it, or worse, aren't even practicing it, that's because of two factors:
1. Weirdness Factor: The ZZP drill seems in some ways to contradict, or at least not to fit very well, with some of the most sacred aspects of conventional Tai Chi aesthetic performance. It requires you to stop briefly at every named pose, and it requires a slight deformation of each pose just prior to surging up the energy. It definitely doesn't fit with anybody's nicey nice little standard of how flowing and fancy/dancy silk-clad Tai Chi oughta look.
2. Depth Factor: This drill is the culmination of many component trainings that can take serious time to master on their own, one by one. That's why it's in the 'Advanced Work' section of the SURGE book. It has pre-requisites of knowing at least a few ZMQ poses, if not the entire set, basic relaxation and ZMQ posture concepts and principles, then you need to understand the whole Zhang Zhuang thing, which itself suffers to a junior degree from these exact same issues (Weirdness and Depth Factors), then you need to understand the idea and practice of pinned arms, which in turn is based on the Relaxation Protocol described in PENG book. And on top of all that, it adds time to your practice if you were, ideally, to integrate it throughout your performance of the whole ZMQ set.
So. I totally get why people don't rave about and for the most part don't even attempt it. And yet, this is the best thing. Anyway I'm going to hammer on it at my Santa Rosa thing (now I'm scaring away the brave souls who pre-signed for this event!).
Meanwhile it is described in the 'Advanced Work' chapter of my book Tai Chi SURGE Radical ZMQ Energetics. The rudiments of it are also partially taught in this video below: