Hi, Daniel.
These are questions that really require a very long and detailed answer from someone like Bruce to fully explore all their aspects. However, here are my two cents.
Bruce has said in several different contexts that the Wu form as he learned it is really good for meditation and for healing back problems. Part of it has to do with some of the details of how the form is done, like how you release to emptiness as a concluding part to each single whip in the form. I think the fact that is a small frame form also contributes to large internal content. He has stated in a few places that originally, Tai Chi wasn’t designed as a container for meditation, but that he learned the tradition of Wu style as meditation from his teacher. I think if you look through his books, specifically Tai Chi -Health for Life, you’ll find the answers you seek there.
About dzogchen vs. taoist meditation: Bruce speaks about this in one of his webinars. I think in the one he did while he was in the Himalayas he specifically talked about his experience in dzoghchen and how it compares with taoist meditation. I’ve looked into dzogchen a bit, but I’m not qualified to answer this question. You could put it to Bruce when you get a chance.
Good luck with your practice.